GIA's Colored Stone Essential's Reference Guide

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ESSENTIAL

Reference Guide

C o l o r e d S t o n e

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ESSENTIAL

Reference Guide

C o l o r e d S t o n e

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©

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Introduction

1 Agate

2 Alexandrite

4 Almandite

6 Amber

8 Amethyst

10 Aquamarine

12 Bloodstone

14 Carnelian

16 Cat’s-Eye

18 Black Chalcedony

20 Chalcedony

22 Citrine

26 Coral

28 Demantoid

32 Emerald

34 Hematite

38 Hessonite

40 Iolite

42 Ivory

44 Jade (Jadeite)

46 Jade (Nephrite)

50 Kunzite

54 Lapis Lazuli

56 Malachite

58 Malaya Garnet

60 Moonstone

62

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Opal

68 Pearl and Cultured Pearl

72 Peridot

76 Pyrope

78 Rhodolite

80 Rose Quartz

82 Ruby

84 Sapphire

88 Shell

92 Smoky Quartz

96 Spessartite

98 Spinel

100 Star Ruby

102 Star Sapphire

106 Tanzanite

110 Tiger’s-eye

112 Topaz

114 Tortoise Shell

118 Tourmaline

120 Tsavorite

124 Turquoise

126 Zircon

130

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Introduction

For centuries, artists and poets have used images of colored stones to express love, passion, and power. People in every era and from all walks of life have adorned themselves with the dra-matic, radiant grace of colored stone jewelry.

This volume, The Essential Colored Stone Reference Guide (The Reference Guide for short), is written in lively, understandable language, with stunning illustrations and an easy, look-it-up format.

Convenient organization makes it easy to put The Reference Guide to work for you. Entries are listed alphabetically by common name. Applicable species, variety, and group names are listed below the heading. You can refer to the Table of Contents if you want to go directly to a specific listing.

Each entry provides clear, practical information that you can use to enrich your sales pre-sentations. For example, a “Care and Cleaning” chart lists common cleaning methods and the relative safety of each method for that particular gem. Common synthetics, treatments, and imi-tations are listed as appropriate, too.

Another feature of each entry is the list of alternative gems at the end of each section. This will be useful to you when, for example, you’re talking with a customer who loves purple, but isn’t sure she wants an amethyst.

Besides practical information, some gem entries include interesting lore. For example, did you know that amber is sometimes called “Gold of the North,” or that emerald was one of Cleopatra’s favorite gems? There’s also a list of the places considered sources of each gem. These bits of information can enhance your presentation and make the gem more interesting to your customer.

The Reference Guide covers gems you’re likely to see in jewelry stores, catalogs, and other retail

settings. But the world of colored stones is vast and varied, and even a guide like this can’t possi-bly include every gem or every property of a given gem. GIA also offers the more advanced—and more technical—Gem Reference Guide, which discusses the gems covered here as well as less-well-known gems, and offers more scientific detail on each gem.

The Essential Colored Stone Reference Guide is your key to the product knowledge you

need to sell color with style and confidence. When new colored stone jewelry appears in your inventory, look it up in the guide. And by all means, use The Reference Guide to help you answer customer questions. You’ll find that with its beautiful photographs and friendly format, it’s a powerful sales tool.

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Agate

_{Agate/Chalcedony}

Agate is a fine-grained chalcedony quartz and one of the first gem materi-als known. Its history goes all the way back to the ancient Egyptians, who first used it for adornment more than 3,000 years ago. Ancient cultures used it in amulets and talismans. They believed that it provided the wearer with a bold heart and pleasant dreams. Roman artisans carved seals from it. Nineteenth century Victorians used it to create beautiful cameos.

The characteristic that sets agate apart from other chalcedonies is its appear-ance: It boasts dramatic curved or angular stripes, or bands of color. These dis-tinctive markings vary widely in color and translucence. The patterns in some agates look like moss, ferns, and trees—even entire landscapes. Others have simple striped patterns of two or more colors. Besides cameos, modern cutting styles that make the most of agate’s unique appearance include cabochons, beads, and carvings.

Fire agate is a relative newcomer to the agate family, discovered in the 1940s. Its mineral layers cause light interference and give it a shimmering iridescence against its brown bodycolor.

Sources

Brazil India Madagascar Mexico United States Uruguay

Hardness & Toughness

Hardness 61_/₂_{to 7 on Mohs scale}

Toughness Good

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Varieties

Eye agate, orbicular agate Banded in concentric rings Landscape agate Chalcedony with colored

pat-terns resembling a landscape Fire agate Iridescent inner layers

Dendritic agate, scenic agate Colorless or white, translucent, with markings resembling trees, ferns, moss, or landscapes Iris agate Semitransparent to translucent,

with iridescent colors

Stability

Environmental Factor Reaction Heat Color may change Light Stable

Chemicals Attacked by hydrofluoric acid; nitric acid may attack dye

Treatments

Treatment Description Purpose Stability Prevalence Dyeing

Heating Improves color Permanent Common

Care and Cleaning

Type of Cleaning Advisability Steam cleaning Not recommended Ultrasonic cleaning Not recommended

Gray South American agate is dyed with inor-ganic dye. Layers absorb dye differ-ently depending on porosity. Improves color, improves band-ing Generally stable under normal con-ditions. May fade or be removed by chemicals. Common Landscape agate Iris agate Produces orange or orangy red color in yellow to brown agate Landscape agate

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Alexandrite

_{Alexandrite/Chrysoberyl}

Alexandrite is a rare chrysoberyl variety with chameleon-like qualities. Its color is a lovely green in daylight or fluorescent light, but it changes to brown-ish or purplbrown-ish red in the incandescent light from a lamp or candle flame.

Alexandrite’s dramatic color change is sometimes described as “emerald by day, ruby by night.” Other gems also change color in response to a change in light source, but this gem’s transformation is so striking that the phenomenon itself is often called “the alexandrite effect.”

Abundant alexandrite deposits were first discovered in 1830, in Russia’s Ural Mountains. Those first alexandrites were of very fine quality, and dis-played vivid hues and dramatic color changes. The gem was named after the young Czar Alexander II, and it caught the country’s attention because its red and green colors mirrored the Imperial Russian flag.

The spectacular Ural Mountain deposits didn’t last forever, and now most alexandrite comes from Sri Lanka, East Africa, and Brazil. The newer deposits con-tain some fine-quality stones, but many possess less precise color change and muddier hues than the nine-teenth century Russian alexandrites. You’ll still find some of the famed Ural Mountain alexandrites in estate jewelry. They remain the quality standard for this phe-nomenal gemstone.

Because of its scarcity, especially in larger sizes, alexandrite is a relatively expensive member of the chrysoberyl family. It shares its designation as a June birthstone with cultured pearl and moonstone.

Sources

Brazil East Africa

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Hardness & Toughness

Hardness 81_/₂_{on Mohs scale}

Toughness Excellent

Stability

Environmental Factor Reaction Heat Stable Light Stable Chemicals None

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Usually safe Steam cleaning Usually safe Warm, soapy water Safe

Imitations

Synthetic color-change sapphire Synthetic color-change spinel

Synthetics

Flux Czochralski

Alternatives

Color-change garnet Color-change sapphire

Alexandrites in incandescent light

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Almandite

_{Almandite/Garnet}

Almandite is probably one of the most familiar of the closely related species that make up the garnet group. It’s a fairly common red garnet, with a color range from orangy red through red to reddish purple.

Almandite was named for Alabanda, an ancient Asian town and an active gemstone trading and fashion-ing center. Ancient Romans often fashioned almandite garnets as thin, hollowed cabochons to bring out the intensity of their color.

Other species in the garnet group come in a variety of hues, from browns and oranges to vibrant greens. As far back as 3100 BC, Egyptians along the Nile worked

gar-net into beads and inlays. Noah is said to have recog-nized garnet’s inner fire and used it as a lamp on the bow of the ark. Garnets of all species, including alman-dite, are considered January birthstones.

Sources

Brazil India Madagascar Pakistan Sri Lanka United States

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Hardness & Toughness

Hardness 7 to 71_/₂_{on Mohs scale}

Toughness Fair to good

Stability

Environmental Factor Reaction

Heat Abrupt temperature changes likely to cause fracturing

Light Stable

Chemicals None, except concentrated hydrofluoric acid

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Usually safe Steam cleaning Never Warm, soapy water Safe

Imitations

Garnet-and-glass doublet

Alternatives

Hessonite garnet Malaya garnet Pyrope garnet Rhodolite garnet Ruby Spessartite garnet Spinel Tourmaline

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Amber

Amber belongs to the category of organic gems—the products of living organisms and biological processes. Amber formed millions of years ago, when sap from ancient trees hardened and fossilized. Stone Age people dis-covered these golden jewels along the shores of the Baltic Sea, and they became perhaps the earliest and most consistently popular ornamental gems. Scientists and collectors treasure amber that contains suspended animal or plant fragments: Fossilized bits of once-living things that were trapped in the hardening amber millions of years ago, creating a fascinating time capsule.

Some types of amber are found in the ground. Other types have been freed and carried by tides and end up on beaches or near-shore areas. The Baltic coast bordering Germany, Poland, and Russia is still a source of amber, which is sometimes called “gold of the North.” Amber’s warm luster is featured in beads, carvings, pendants, and cabochon rings, as well as dec-orative items like cups, bowls, snuff boxes, and umbrel-la handles.

Amber’s colors range from whites, yellows, and oranges to reds and browns. Clear material is preferred in the US, cloudy in Europe and North Africa. Heating cloudy amber in oil clarifies it. Heat treatment can also produce disk-like stress fractures and create an attrac-tive product called sun-spangled amber.

Sources

Dominican Republic Germany Mexico Poland Russia

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Hardness & Toughness

Toughness Poor

Stability

Heat Burns at low temperatures Light May darken with age

Chemicals Attacked by acids, caustics, alcohol, gasoline

Treatments

Treatment Purpose Stability Prevalence Detection Heating in oil Stable Occasional May be detectable Heating Lightens color Stable Occasional Undetectable

Stable Common May be detectable Dyeing Darkens color May fade Occasional May be detectable

Care and Cleaning

Type of Cleaning Advisability Steam cleaning Never

Ultrasonic cleaning Never

Warm, soapy water Safe, but hard brushes may scratch

Imitations

Ambroid (reconstructed or pressed amber) Copal (a natural resin, younger than amber) Plastic Yellow glass Produces sun spangles Clarifies cloudy amber

Amber pendant showing sun spangles

Heating (some-times with oil)

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Amethyst

_{Amethyst/Quartz}

Amethyst has been the most prized member of the quartz family for cen-turies. Early Greek legends, and its wine-purple color, associated amethyst with Bacchus, the god of wine. Other legends led to beliefs that amethyst gems kept their wearers clear-headed and quick-witted in battle and in their business affairs. It’s no wonder that fine amethyst adorns the fingers of bish-ops and the coronation regalia of British royalty.

Russia was once the main source of amethyst, but near the turn of the twen-tieth century, new deposits were discovered in South America. After that, it became more widely available, but no less treasured. Amethyst comes in a range of sizes, and the color selection ranges from palest lilac to rich purple. Experts consider African amethyst’s royal purple with reddish overtones to be the gem’s finest color.

A closely related quartz variety called ametrine con-tains a striking mixture of two contrasting quartzes— purple amethyst and yellow citrine. Ametrine deposits are found in Brazil and Bolivia.

Amethyst is the birthstone for February.

Sources

Brazil Major source India Namibia Sri Lanka United States Uruguay Zambia

Hardness & Toughness

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Stability

Heat Abrupt temperature change may fracture stone, can alter color Light Some amethyst may fade

Chemicals Damaged by hydrofluoric acid, ammonium fluoride, alkalies

Treatments

Treatment Purpose Stability Prevalence Detection Heating Excellent Occasional Undetectable

Care and Cleaning

Type of Cleaning Advisability Steam cleaning Not recommended Ultrasonic cleaning Usually safe Warm, soapy water Safe

Imitations

Glass

Purple synthetic corundum

Assembled stone (synthetic spinel triplet)

Synthetics

Hydrothermal

Alternatives

Iolite Rhodolite garnet Sapphire Spinel Tanzanite Topaz Tourmaline Lightens color or produces citrine or green quartz Carved amethyst

Contemporary amethyst and diamond pendant

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Aquamarine

_{Aquamarine/Beryl}

Aquamarine’s cool blue hues are reflected in its name, which comes from the Latin for “sea water.” Medieval sages prescribed water touched by aqua-marine for a host of ills, including those affecting the eyes and lungs. They promised the virtues of insight and foresight to the gem’s wearers.

Aquamarine crystals can grow to huge sizes, and are usually blessed with excellent clarity. Gem bodycolors range from greenish blue to blue-green in light tones. Usually, the color is more intense in larger stones, but some aquamarine from Africa displays deeper blues in faceted stones of less than 5 cts. Brazil supplies the most aquamarine to the modern market.

Like emerald, aquamarine is a member of the beryl species. The gem is March’s birthstone.

Sources

Australia

Brazil Major source China

Kenya Madagascar Mozambique

Nigeria Known for intense color in smaller sizes (under 5 cts.)

Pakistan United States Zambia

Hardness & Toughness

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Stability

Heat Exposure to heat not recommended Light Stable

Chemicals Attacked by hydrofluoric acid

Treatments

Treatment Purpose Stability Prevalence Detection Heating Very good Routine Undetectable

Care and Cleaning

Type of Cleaning Advisability

Ultrasonic cleaning Usually safe, unless stone contains feathers or liquid inclusions

Steam cleaning Usually safe, unless stone contains feathers or liquid inclusions

Warm, soapy water Safe

Imitations

Glass Synthetic spinel

Alternatives

Blue topaz Sapphire Spinel Tanzanite Tourmaline Removes yel-low, resulting in purer blue color A 32.10-ct. heart-shaped aquamarine from Brazil

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Bloodstone

_{Bloodstone/Chalcedony}

Bloodstone is an opaque to semitranslucent variety of chalcedony. Its bold coloring—dark green flecked with red—has intrigued people for centuries. The ancient Greeks named it heliotrope (“sun-turner”) because they observed that it flashed scarlet when they lowered it into water and pointed it toward the sun. Many people thought it colored water red for the same reason. Citizens of Medieval and Renaissance Europe honored bloodstone as a talisman that stirred passion, stopped bleeding, and brought healing.

Rich men in the time of King Solomon prized the gem for use in their seal rings, and it’s still set in men’s jewelry today. Bloodstone is also popular in Christian jewelry because its distinctive pattern reminded early Christians of the blood of Christ at the foot of the cross.

Bloodstone is the alternate birthstone for March.

Sources

Australia Brazil China India United States

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Hardness & Toughness

Toughness Good

Stability

Heat Color may change

Light Stable

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Not recommended Steam cleaning Not recommended Warm, soapy water Safe

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Carnelian

_{Carnelian/Chalcedony}

Carnelian is a semitransparent to translucent variety of chalcedony. Gem specialists believe it was named after the kornel cherry, which grows in the same warm shades as the gem: Yellowish orange to orangy red to brownish orange. It’s often fashioned into beads or cameos to show off its color.

Ancient civilizations believed that carnelian transformed poor or timid speakers into eloquent ones. Carnelian’s history began in India, where it was mined as early as the fourth century BC.

Sources

Brazil India Uruguay

Hardness & Toughness

Toughness Good

Stability

Environmental Factor Reaction Heat Color may change Light Stable

Chemicals Attacked by hydrofluo-ric acid

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Treatments

Treatment Purpose Stability Prevalence Detection Heating Improves color Stable Common Undetectable

Care and Cleaning

Imitations

Glass Plastic

Alternatives

Amber Fire opal Jade Sard chalcedony

Carnelian intaglio ring Carnelian intaglio

Roman carnelian intaglio from the first century BC

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Cat’s-Eye

_{Cat’s-Eye/Chrysoberyl}

This gem, with its band of reflected light across the middle, has always reminded observers of the eye of a cat. The cat’s-eye effect, also called cha-toyancy, is caused by parallel needle-like inclusions within the stone. The gem was once known as cymophane—Greek for “waving light.” In some cultures, its distinctive appearance made it the preferred treatment for all sorts of eye ailments.

Chatoyancy appears in other gemstones, but fine-quality cat’s-eye chrysoberyl sets the standard. It’s also the most valuable cat’s-eye stone. It’s durable as well as attractive, which makes it popular in men’s rings, cufflinks, and tie tacks. The cabochon cut brings out its cat’s-eye effect to best advantage.

Cat’s-eye chrysoberyl ranges from brown to greenish yellow. The finest quality specimens boast a golden color, with bands that span the entire length of the gem. The bands themselves are distinct, silvery-white, and straight.

The chatoyant band in cat’s-eyes will appear to blink when you hold the stone between two light sources, then rotate it. As you turn the stone, the eye splits into two bands that move apart, then back together. This effect is called “opening and closing.”

Cat’s-eyes display another impressive effect, called milk and honey. With the light positioned perpendicular to the chatoyant band, the side nearest the light shows the stone’s original bodycolor while the other side has a milky appearance.

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Sources

Brazil East Africa Sri Lanka

Hardness & Toughness

Hardness 81_/₂_{on Mohs scale}

Toughness Excellent to good

Stability

Environmental Factor Reaction Heat Stable Light Stable Chemicals None

Care and Cleaning

Imitations

Cat’s-eye glass

Alternatives

Cat’s-eye quartz Cat’s-eye tourmaline Tiger’s-eye quartz

Cat’s-eye chrysoberyl set in art deco-style platinum ring with diamonds

72.68-ct. cat's-eye chrysoberyl cabochon with a 317.7-ct piece of rough from Brazil

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Black Chalcedony

Natural black chalcedony is extremely rare. The jewelry industry common-ly calls dyed black chalcedony, which is more common, “black onyx.” This always-stylish gem was prominent in the Art Deco jewelry of the 1920s and 1930s. Jewelry designers of the time often set it in platinum with diamonds, or with the colorless quartz variety known as rock crystal.

Because “basic black” is always in style, so is black chalcedony. It has the added advantages of good durability, low cost, and availability in an almost unlimited range of sizes. It’s one of the most popular gems for beads, cabochons, tablets, inlays, and carvings. You’ll often find this stone in men’s

jewelry.

Black chalcedony is also commonly used as a back-ing for opal doublets and triplets. In doublets, pieces of opal too thin to use alone are often cemented to a tablet of black chalcedony. This dramatizes the opal’s play of color and gives strength to the assembled stone. A triplet requires the addition of a protective top made of rock crystal quartz or some other hard, color-less material.

Sources

Brazil Gray chalcedony, later dyed black

Hardness & Toughness

Hardness 61/₂ to 7 on Mohs scale

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Stability

Heat Color may change

Light Stable

Chemicals Attacked by hydrofluoric acid; nitric acid may

attack dye

Treatments

Treatment Purpose Stability Prevalence Detection

Care and Cleaning

Imitations

Glass Plastic

Alternatives

Hematite Jadeite jade Nephrite jade Onyx Boiling in a solution of sugar and water, then soaking in sulfu-ric acid. Usually described as “dyeing.” Produces black color in gray chalcedony Stable under normal condi-tions Routine. Virtually all black chal-cedony is dyed. No tests. Treatment is assumed.

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Chalcedony

Chalcedony is one of the world’s oldest, most abundant, and most popular gems. It was named for the ancient Turkish seaport of Chalcedon (now called Kadikoy). Many cultures throughout history have used it for a vari-ety of purposes. Many considered it a powerful talisman. In the third and fourth centuries, Greek sailors wore chalcedony amulets as protection against drowning. As late as the 1700s, many Europeans believed chal-cedony would drive away ghosts and bad spirits.

Chalcedony is fairly affordable, and it comes in an incredibly wide range of colors and patterns. These two factors make it very popular with gem and mineral collectors. In jewelry, you’ll see it most often as beads, cabochons, tablets, and carvings. Imaginative designers use chalcedony in some of the most cutting-edge creations available on the market.

Mineralogists consider chalcedony a variety of quartz, but gemologists and gem professionals treat the two as separate species. The difference between them is that quartz occurs in large crystals, while the individual crystals that make up chalcedony are so small that it takes very high magnification to see them.

Sources

See Agate, Bloodstone, Carnelian, and Onyx and Sardonyx for sources of those gems.

Australia Chrysoprase Brazil Many varieties Czech Republic Chrysoprase Germany Jasper

Iceland Milky chalcedony

India Chrysoprase, milky chalcedony Italy Jasper

Mexico Chrysocolla-in-chalcedony Russia Jasper, milky chalcedony Scotland Jasper

United States Amethystine chalcedony, chryso-colla-in-chalcedony, chrysoprase, jasper, milky chalcedony

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Hardness & Toughness

Toughness Good

Varieties

Variety Name Appearance and Comments

Agate Translucent to opaque, with curved or angular color banding; also patterns such as “moss” and “land-scape.” For additional information, see Agate. Amethystine chalcedony Semitranslucent to opaque purple. Often marketed as

“purple agate” or under the trade name “damsonite.” Bloodstone Semitranslucent to opaque, dark green with red to

brownish red spots. For additional information, see Bloodstone.

Carnelian Semitransparent to translucent, yellow-orange to orangy red, often slightly brownish. For additional information, see Carnelian.

Chrysocolla-in-chalcedony Translucent to semitranslucent, intense light blue or blue-green. Can resemble fine turquoise. One of the most valuable chalcedony

vari-eties.

Chrysoprase Semitransparent to translucent, light to medium yellowish green. The name comes from Greek words meaning “golden apple,” and is ethically used only for natu-ral-color (not dyed) material. Dendritic agate Chalcedony with dark inclusions

resembling tree branches. Fire agate Semitranslucent to opaque, with

iridescent colors against a brown bodycolor.

Iris agate Semitransparent to translucent, with iridescent colors (phenomenon best seen on thin slices in transmitted light)

Jasper Opaque; any color or combination of colors except solid black or material known by another name (agate, black chalcedony, carnelian,

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Milky chalcedony Semitransparent to translucent, nearly colorless to white or light gray. Often sold as an alternative for moonstone.

Onyx Translucent to opaque, with straight, parallel bands of different colors. For additional information, see Onyx and Sardonyx.

Sard Semitransparent to translucent, dark brown, brownish orange, or brownish red (darker and less saturated color than carnelian).

Sardonyx Onyx with sard colors alternating with either white or black. For additional information, see Onyx and Sardonyx.

Stability

Heat Color may change, especially if dyed Light Stable

Chemicals Attacked by hydrofluoric acid; nitric acid may attack dye in treated material

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Treatments

Treatment Purpose Stability Prevalence Detection Dyeing Common

* If there is any doubt, send the gem to a gemological laboratory for verification. Even then, some colors are not detectable.

Care and Cleaning

Imitations

Glass Plastic

Alternatives

Amber Hematite Jadeite jade Lapis lazuli Malachite Moonstone Nephrite jade Rose quartz Shell Tiger’s-eye Turquoise Produces a wide variety of colors Generally sta-ble under nor-mal conditions Some colors detectable by a trained gemolo-gist or gemologi-cal laboratory.* Often assumed because of unnat-ural color. Dendritic chalcedony

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Citrine

_{Citrine/Quartz}

Citrine is one of the US birthstones for November (the other is topaz). It’s a quartz variety, and the top-selling transparent gem in the yellow to orange color range. Its name was derived from the Latin word citrus, meaning “cit-ron” (a fruit closely related to the lemon). This gem combines a warm, attractive color with good wearability and a moderate price—an unbeatable combination for many customers.

Citrine comes in an exceptionally wide range of sizes. The largest trans-parent faceted gem on record (in terms of dimensions and volume) is a cit-rine. It measures 25.5 cm ˘ 14.1 cm ˘ 10.0 cm (9.9 in. ˘ 5.5 in. ˘ 3.9 in.), and weighs 19,548 cts. (3.9 kg/8.6 lb.). Jewelry-sized citrines are readily avail-able in weights of up to 20 cts. and more.

Most citrine is faceted in traditional rounds and fancy shapes, but you’ll also find it fashioned into more unusual cuts and carvings. Leading jewelry designers use citrine alone, in combination with diamonds, and in multicol-ored creations alongside gems with contrasting colors— amethyst, aquamarine, blue topaz, and others.

Before the development of modern gemology, citrine was traditionally confused with topaz because of their similar colors.

Sources

Bolivia Brazil Spain

Hardness & Toughness

Hardness 7 on Mohs scale Toughness Good

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Stability

Heat High heat can cause color loss; sudden or extreme temperature change can cause fracturing

Light Stable

Chemicals Soluble in hydrofluoric acid and ammonium fluoride; very slightly soluble in alkalis

Treatments

Treatment Purpose Stability Prevalence Detection Heating

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Usually safe Steam cleaning Not recommended Warm, soapy water Safe

Imitations

Glass Plastic

Synthetic hydrothermal quartz Synthetic sapphire Synthetic spinel

Alternatives

Amber Carnelian Chrysoberyl Malaya garnet Sapphire Smoky quartz

6.20-ct. citrine from Brazil

Carved citrine

Citrine Quartz from Brazil

Produces color— changes amethyst to cit-rine Permanent under normal condi-tions Routine. Most citrine is pro-duced by heat treating amethyst. Undetectable. Treatment is assumed.

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Coral

For thousands of years, cultures around the world have prized coral as a gem and credited this product of the sea with magical powers. First century Romans used it to ward off evil and to impart wisdom. It’s still worn in modern-day Italy as protection against the “evil eye” and as a cure for sterility.

There are two basic types of gem coral. One type comes in a variety of lighter shades: White, cream or pink, various shades of red or orange, and occasionally blue, purple, or light grayish violet (known as “laven-der” in the trade). The other coral type is black, dark brown, or sometimes light brownish yellow (often called “golden”).

All coral is composed of the remains of skeleton-like support structures that were built by colonies of tiny marine animals. These coral polyps, as they’re called, are close relatives of the more familiar coral reef builders.

Coral jewelry, in the form of beads, cabochons, and especially small carvings and cameos, has been popular in Europe since Roman times. Its popularity is strong in both North and South America. At one time, Asian countries used coral more often for large carvings, but Western influences prompted increased production and popularity of coral jewelry in the twentieth century.

World demand for coral jewelry remains high, even though a number of factors have combined to drastically reduce the supply of new material in recent decades. These factors include pollution, over-harvesting, and increasing national and international environmental pro-tection efforts.

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Unfortunately, pollution and depletion have devastated these waters. Australia—another once-important source—now hibits the export of all native coral. The state of Hawaii pro-tects black “King’s” coral as an endangered species. All these factors limit modern supplies of coral, but the avail-ability of high-quality older pieces guarantee it a perma-nent place in the antique market.

Sources

Japan Malaysia Philippines

Hardness & Toughness

Hardness 3 to 4 on Mohs scale Toughness Fair to good

Stability

Heat Blackens or burns if exposed to the flame of a jeweler’s torch

Light Generally stable; dyed material may eventually fade

Chemicals Easily attacked by acids and other chemicals

Chimera bracelet bangle by Cartier (not signed) of carved coral set with diamonds in platinum

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Treatments

Treatment Purpose Stability Prevalence Detection Dyeing Occasional

Stable Common

* If there is any doubt, send the gem to a gemological laboratory for verification. Deepens or

changes color, usually to pink or red, but any color is possi-ble Dye can be affected or removed by solvents, and can fade under prolonged exposure to strong light Might be detectable by a trained gemolo-gist or gemo-logical labora-tory*

Fills and hides cavities and fractures

Stable under normal condi-tions, but can be damaged or destroyed by high heat and solvents Common in low-quality material Detectable by a trained gemolo-gist or gemo-logical labora-tory Impregnation with epoxy resin or glue-like sustances Bleaching in hydrogen per-oxide solution Produces “golden” color in black coral Detectable by a trained gemolo-gist or gemo-logical labora-tory

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Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Risky

Steam cleaning Never Warm, soapy water Safe

Imitations

Glass Plastic

Alternatives

Amber Carnelian Chalcedony Cultured pearl Jadeite jade Nephrite jade Rose quartz Shell

Carved and rough coral

Different types and colors of coral Enamel and coral beads torsade necklace

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Demantoid

_{Demantoid/Andradite/Garnet}

Demantoid means “diamond-like” in Dutch, the language of Renaissance diamond cutters. Its name reflects the fact that, while demantoid is much softer than diamond, its dispersion is higher, so its flashes of rainbow color are very noticeable, especially in lighter-colored stones. This lush green gem is a variety of andradite and a member of the garnet group.

Demantoid displays intense color in the green to yellow-green range. Under the microscope, fine demantoid has another telltale signature: Its classic “horse-tails.” They are wisps of long, golden, fiber-like inclusions that radiate from a central point.

Demantoid was discovered in Russia’s gem-rich Ural Mountains in 1868. Tiffany and Company’s chief gem buyer, George Kunz, fell in love with the newly discov-ered gem, and the company bought up all that they could get. Tiffany marketed it as an appealing emerald alternative. Even though it was rarely available in sizes larger than 2 cts., demantoid adorned much Victorian jewelry crafted between 1895 and 1915.

The historic Russian source doesn’t yield much demantoid any more. In fact, the scarcity of fine-quali-ty demantoid has made it a prized collector’s stone. Recent discoveries in Namibia, however, have increased the availability.

Demantoid joins the rest of the garnet group as a January birthstone.

Sources

Namibia Russia Zaire

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Hardness & Toughness

Toughness Fair to good

Stability

Heat Abrupt temperature changes likely to cause fracturing

Light Stable

Care and Cleaning

Ultrasonic cleaning Usually safe, risky if contains liquid inclusions

Imitations

Colored CZ Colored YAG Garnet-and-glass doublet

Alternatives

Emerald Green sapphire Green zircon Peridot Tourmaline Tsavorite garnet

Close-up of the horsetail inclusion in a demantoid

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Emerald

_{Emerald/Beryl}

Emerald’s lush green has soothed souls and excited imaginations since antiquity. Its name comes from the ancient Greek word for green, “smarag-dus.” Rome’s Pliny the Elder described emerald in his Natural History, pub-lished in the first century AD: “…nothing greens greener” was his verdict.

He described the use of emerald by early lapidaries, who “have no better method of restoring their eyes than by looking at the emerald, its soft, green color comforting and removing their weariness and lassitude.” Even today, the color green is known to relieve stress and eye strain.

The first known emerald mines were in Egypt, dating from at least 330

BCinto the 1700s. Cleopatra was known to have a

pas-sion for emerald, and used it in her royal adornments. Emeralds from what is now Colombia were part of the plunder when sixteenth-century Spanish explorers invaded the New World. The Indians had already been using emeralds in their jewelry and religious cere-monies for 500 years. The Spanish, who treasured gold and silver far more than gems, traded emeralds for pre-cious metals. Their trades opened the eyes of European and Asian royalty to emerald’s majesty.

Emerald is often mined and sold under peril—the natural resource Colombians cherish is also coveted by underworld drug traders. The availability of fine-quality emerald is limited, and emerald was plagued in the late 1990s by negative publicity about treatments commonly used to improve its clarity.

Emerald is the most famous member of the beryl family. Legends gave it the power to make its wearer more intelligent and quick-witted. It was once also believed to cure diseases like cholera and malaria. Its color reflects new spring growth, which makes it the perfect choice of a birthstone for the month of May. It’s

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Sources

Afghanistan Brazil

Colombia One of the largest commercial producers: Fine Colombian emeralds are highly regarded for their excellent color

Pakistan Russia

Zambia A major commercial source: Zambian emeralds tend to have good clarity

Zimbabwe The Sandawana Valley is a famous source

Hardness & Toughness

Toughness Poor to good

Stability

Heat May cause fractures

Light Fracture fillings may dry out or alter under intense light

Chemicals Fracture fillings may be affected by any type of chemical, emerald itself is resistant to all acids except hydrofluoric

Emerald cross recovered from Nuestra Senora de Atocha Galleon

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Treatments

Treatment Description Purpose Stability Prevalence Fracture Filling Not permanent Routine

Dyeing Not permanent Rare

Coating Not permanent Rare

Care and Cleaning

Most emeralds have been fracture-filled. An emer-ald’s appearance may change over time due to the instability of its filling material. Depending upon their condition, emeralds may be retreated by an experienced professional.

Type of Cleaning Advisability Steam cleaning Never

Ultrasonic cleaning Never

Warm, soapy water Usually safe. Avoid vigorous scrubbing Filling

surface-reaching frac-tures with col-orless oils or resins. Simply called “oiling” in the trade when colorless oils are used.

Improves clari-ty, improves color

Adding col-orant to the oils or resins used in the fracture-filling process

Improves emer-ald color, gives light-colored beryls an emer-ald green color Covering a light-colored beryl with a green plastic Creates an emerald imita-tion

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Imitations

Green glass

Synthetic spinel triplet

Synthetics

Flux Hydrothermal

Alternatives

Alexandrite Demantoid garnet Diopside Jadeite Peridot Sapphire Tourmaline Tsavorite garnet Zircon

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Hematite

Hematite’s shiny metallic luster and dark gray to black color give it a spe-cial beauty and appeal that’s shared by few other stones. It’s inexpensive, and available in a wide range of sizes, so it’s a traditional favorite for men’s rings—especially when it’s engraved with a warrior’s head or animal motif. It’s also widely used for pendants as well as bead necklaces and bracelets.

Hematite has the highest density (weight-to-size ratio) of any commonly available natural gem. This gives hematite jewelry a weighty feel and an aura of value. Its high density has a down side for some wearers of hematite earrings, though: Large pendant and hoop styles are too heavy to wear

com-fortably for long periods.

Hematite is composed of iron oxide, so it’s chemi-cally the same as common rust. The name comes from the Greek word haima, which means “blood”—refer-ring to the red color of the mineral in its powder form. Hematite’s name means, literally, “blood stone.”

People in ancient mideastern cultures believed that hematite would ensure victory in lawsuits and favorable judgments from kings and others in authority. During Roman times, the gem was associated with Mars, god of war: It was believed to protect a warrior who rubbed it on his body. Native Americans also used powdered hematite as a pigment for war paint.

Sources

England Norway Sweden United States

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Hardness & Toughness

Hardness 51_/₂_{to 6}1_/₂_{on Mohs scale}

Toughness Fair

Stability

Heat May become magnetic Light Stable

Chemicals Soluble in hydrochloric acid

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Safe

Steam cleaning Safe Warm, soapy water Safe

Imitations

Imitation hematite—usually made mostly of compressed iron, and often stamped with an intaglio design. Once marketed as “hemetine,” but that trade name was ruled misleading by the FTC.

Alternatives

Black chalcedony Cultured pearl Jadeite jade Nephrite jade

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Hessonite

_{Garnet/Grossularite/Hessonite}

Hessonite is a variety of grossularite garnet. Its close relative, tsavorite, is also a grossularite variety. But hessonite’s warm brownish yellows, brownish oranges, and brownish reds make quite a contrast to tsavorite’s cool green. Because of hessonite’s color, as well as its historic connection with the spice-producing country of Sri Lanka, this garnet is also known as “cinnamon stone.”

Sources

Brazil Canada Madagascar Mexico Sri Lanka Tanzania US

Hardness & Toughness

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Stability

Heat Abrupt temperature change likely to cause fracturing

Light Stable

Care and Cleaning

Ultrasonic cleaning Usually safe, unless liquid inclu-sions are present

Alternatives

Almandite Citrine Fire opal Sapphire Spessartite Topaz Zircon

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Iolite

Iolite gets its name from the Greek word for violet, and like that flower, its cool shades range from light to dark blue and violet. It’s a transparent to translucent gem that’s strongly pleochroic. This means that it shows dif-ferent colors from difdif-ferent viewing angles. From some angles, blue iolite can actually appear colorless. Other pleochroic colors include gray, violet, or yellow. This optical property allows the gem to act as a strong light-polarizing filter, a feature that Viking navigators found useful. To locate the sun—and chart their position—on overcast days, they viewed the sky through a thin piece of iolite.

Sources

Brazil India Madagascar Namibia Norway Sri Lanka Tanzania

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Hardness & Toughness

Hardness 7 to 71/₂on Mohs scale

Toughness Fair

Stability

Environmental Factor Reaction Heat Can be damaged Light Stable

Chemicals Attacked by acids

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Risky

Steam cleaning Risky Warm, soapy water Safe

Imitations

Glass

Alternatives

Blue topaz Sapphire Tanzanite

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Ivory

Ivory is an organic material that has been part of human art and culture for thousands of years. It has always symbolized the strength, life force, and majesty of nature, and ivory objects served ceremonial, ornamental, and utilitarian purposes for most of the great civilizations. In Europe, archaeol-ogists unearthed ivory carvings and artifacts that are as much as 30,000 years old. The Egyptians were crafting exquisite ivory ornaments by 8000

BC. Its easy workability and color palette—ranging from soft or radiant

whites to warm light or golden brownish yellows—made ivory a prized medium for artisans, gem carvers, and jewelry designers.

Today, ivory is one of the world’s most controversial gem materials. It comes from the tusks or teeth of certain mammals, and those mammals must die in order to yield their treasure. The most familiar ivory source is the ele-phant. Others include the hippopotamus, narwhal, sperm whale, walrus, and

warthog. Most are endangered species.

International prohibitions exist (under the UN Convention on the International Trade in Endangered Species of Wild Flora and Fauna [CITES]) against trade in ivory. More than 100 nations are parties to CITES, and most of them have enacted laws to reinforce the ban. Beyond this, environmental and animal-rights activists militantly oppose commerce in ivory, and most consumers shun it as well. Despite all this, there’s still a strong market for ivory, which is now supplied almost exclusively by criminal means.

A limited alternative to ivory is fossil ivory, which comes mostly from the remains of woolly mammoths that inhabited the northern hemisphere more than 10,000 years ago. Its main source is the Russian Siberian region. There’s also a legitimate collector’s market in antique ivory. Unfortunately, some dishonest traders use treatments to artificially “age” new ivory, thus avoiding the legal prohibitions.

Hardness & Toughness

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Stability

Heat Causes shrinkage, cracking, and discoloration

Light Yellows with age

Chemicals Attacked by many chemicals; soft-ened by nitric and phosphoric acid

Treatments

Treatment Purpose Stability Prevalence Detection Bleaching Stable Common Undetectable Dyeing Stable Common

Heating Stable Undetermined

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Never

Imitations

Glass Plastic

Alternatives

Chalcedony Cultured pearl Jadeite jade Lightens or removes stains Can impart any color, but usually done to simulate the appearance of antique ivory Usually unde-tectable unless the color is unnatural in appearance Darkens the color to simulate the appearance of antique ivory Usually unde-tectable

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Jade [Jadeite]

There are two different gem minerals that are correctly called jade, and jadeite is one of them. (The other is nephrite.) Jadeite comes in a wide range of attractive colors: Many shades of green, yellow, and reddish orange, plus white, gray, black, brown and lavender (which often refers to light purple or light grayish violet). The coloration is often streaked or mottled, giving jadeite gemstones an interesting visual texture that carvers can use to create imaginative and intriguing effects.

The finest quality jadeite—almost transparent with a vibrant emerald-green color—is known as “Imperial jade.” The royal court of China once had a standing order for all available material of this kind, and it’s one of the world’s most expensive gems. Other highly valued jade varieties include “kingfisher jade,” with a green color that’s only slightly less vivid than Imperial; “apple jade,” which is an intense yellow-ish green; and “moss-in-snow jade,” which is translu-cent white with bright green veining, patches, or spots. The most outstanding examples of these are almost always bought and sold in the Asian market.

The Maya and the Aztecs prized jadeite from Central America. They used it for medicinal purposes as well as for jewelry, ornaments, and religious artifacts. The name jade comes from the Spanish expression piedra de ijada—literally “stone of the pain in the side.” Early Spanish explorers named it after they saw natives hold-ing pieces of the stone to their sides to cure or relieve various aches and pains.

It was in China—where the gem-carving tradition was already thousands of years old—that jadeite reached its peak as an important artistic medium. The first jadeite reached China from Burma (now known as Myanmar) in the late 1700s, and late eighteenth and

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early nineteenth century carvers created masterpieces that are still unsur-passed in concept, design, and technical execution.

Jadeite is a favorite medium for lapidary artists around the world. This is especially true in China, where jade carving is still a national art form. It’s a popular material for beads, cabochons, bangle bracelets, and small carv-ings. Because of its exceptional strength and toughness, it’s one of the few gems that can be used to make hololiths—bracelets or rings carved entirely from a single piece of stone, with no supporting metalwork or mounting.

Jadeite symbolizes prosperity, success, and good luck. It’s one of the top-selling gems in Asia, but its versatile beauty and cultural associations have also earned it an important place in the global gem and jewelry market.

Sources

Guatemala Myanmar (Burma) Russia United States

Hardness & Toughness

Toughness Exceptional

Stability

Heat Damaged by a jeweler’s torch Light Stable

Chemicals Slightly affected by warm acids

Various colors of jadeite.

Major source of finest quality material

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Treatments

Treatment Purpose Stability Prevalence Detection Common

Common

Heating Stable Unknown Undetectable

* If there is any doubt, send the gem to a gemological laboratory for verification. Dyeing (Referred to as “C jade”) To add color (usually green or lavender) in white or light-colored material Fair to good. May fade with time Detectable by a trained gemolo-gist or gemologi-cal laboratory* Impregnation with paraffin wax Hides fractures and improves polish appear-ance

Fair. Heat will destroy the treatment Detectable by a trained gemolo-gist or gemo-logical labora-tory* Bleaching and impregnation with plastic-type polymer resin. (A two-step pro-cess.) (Referred to as “B jade”) Improves color; fills and hides fractures and cavities; improves pol-ish appearance Stable under normal condi-tions. High heat can damage or destroy the polymer Sometimes detectable by a trained gemolo-gist. Definite proof usually requires advanced testing by a gemological laboratory* Produces brown or red-dish color in some material

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Care and Cleaning

Ultrasonic cleaning Safe except for wax-impregnated material

Steam cleaning Safe except for wax-impregnated material

Warm, soapy water Safe

Imitations

Glass Plastic

Synthetics

Synthetic jadeite has been produced on a limited basis. Identification requires advanced testing. (If there is any doubt, send the gem to a gemo-logical laboratory for verification.)

Alternatives

Agate Amber Black chalcedony Bloodstone Carnelian Chrysoprase chalcedony Malachite Nephrite jade Onyx Rose Quartz Shell Turquoise Jadeite carving

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Jade [Nephrite]

Nephrite jade has its cultural roots in the smoke-dimmed caves and huts that sheltered prehistoric humans. In China, Europe, and elsewhere around the world, Stone Age workers shaped this toughest of minerals into weapons, tools, ornaments, and ritual objects. Their carvings invoked the powers of heaven and earth and mystic forces of life and death. The ancient relation-ship between this gemstone and humanity persisted into modern times among native societies in New Zealand and parts of North America. In China it evolved into an artistic tradition that has flourished for more than 3,000 years.

Nephrite is one of the two distinct minerals accepted as jade in the international gem and jewelry industry. (Jadeite is the other.) It ranges from translucent to opaque and can be light to dark green, yellow, brown, black, gray, or white. Its colors tend to be more muted than jadeite’s, and they’re often mottled or streaked. Its name comes from Latin words meaning “kidney stone”—a reference to the medicinal use of jadeite (with which nephrite was long confused) by Native Americans.

Generally inexpensive, extremely wearable, and available in all sizes, nephrite is often used in jewelry for beads, cabochons, bangle-type bracelets, and carv-ings. The Chinese associate it with clarity of mind and purity of spirit. Some of the ancient symbolic motifs still used in modern jade carvings (both nephrite and jadeite) include:

Bat—happiness Butterfly—long life

Dragon—power, prosperity, and goodness Peach—immortality

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Sources

Canada China New Zealand Russia Taiwan United States

Hardness & Toughness

Toughness Exceptional (the toughest known gem)

Stability

Heat Damaged by a jeweler’s torch Light Stable

Chemicals Slightly affected by warm acids

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Treatments

Treatment Purpose Stability Prevalence Detection Dyeing Occasional

Common

Heating Stable Unknown Undetectable

* If there is any doubt, send the gem to a gemological laboratory for verification.

Care and Cleaning

Ultrasonic cleaning Safe except for wax-impregnated material. Steam cleaning Safe except for wax-impregnated material. Warm, soapy water Safe

Produces or improves color (usually green) in light-colored material Variable, depending on the type of dye

Detectable by a trained gemolo-gist or gemo-logical labora-tory* Impregnation with paraffin wax Hides fractures and improves polish appear-ance

Fair. High heat will destroy the treatment Detectable by a trained gemolo-gist or gemo-logical labora-tory* Lightens color of dark green mate-rial. Also dark-ens or “ages” white, yellow, or brown material

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Imitations

Glass Plastic

Alternatives

Agate Amber Black chalcedony Bloodstone Carnelian Chrysoprase chalcedony Hematite Jadeite jade Malachite Onyx Rose quartz Shell Turquoise

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Kunzite

_{Kunzite/Spodumene}

George Frederick Kunz (1856-1932) was a pioneer gemologist and longtime buyer for Tiffany and Company. He was also a world-recognized expert on—and avid promoter of—American gemstones. In 1902, he identified a new gem-quality variety of the mineral spodumene in San Diego County, California. The new gem was named kunzite in his honor.

This transparent stone’s light and delicate—but often bright—“rose” pink to bluish purple “lilac” color has endeared it to gem lovers and connois-seurs, especially in the US and Japan. The most valued kunzite colors are the more intense pinks and bluish purples, but the lighter pinks are the most common. Kunzite is very popular with customers look-ing for gems in soft pastel colors.

The supply of fine-quality kunzite is limited, but var-ious faceted fancy shapes are usually available in sizes as large as 50 cts. The gem has poor toughness due to cleavage, and its attractive color can fade with exposure to bright light. Because of these factors, kunzite is a gem that requires special care, but many consider the extra care worthwhile because of its beauty.

Sources

Afghanistan Brazil Madagascar United States

Hardness & Toughness

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Stability

Heat High heat can cause color loss; sudden temperature change can cause breaks

Light Bright light causes the color to fade

Chemicals Very slowly attacked by concentrated hydrofluoric acid

Treatments

Treatment Purpose Stability Prevalence Detection Irradiation Unknown Undetectable

Care and Cleaning

Type of Cleaning Advisability Ultrasoniccleaning Never

Imitations

Glass Synthetic sapphire Synthetic spinel

Alternatives

Amethyst Morganite Rhodolite garnet Rose quartz Sapphire Spinel Topaz Produces kunzite from colorless or light-colored spodumene Color fades in bright light (as does untreated material)

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Lapis Lazuli

Lapis lazuli belongs to a small category of gems called “rocks” because it’s an aggregate of several different minerals. (A mineral is a natural inor-ganic material with a specific—and unique—chemical composition and crystal structure). It’s often simply called “lapis” in the trade.

Lapis is typically opaque, and its colors are medium to dark greenish “navy” blue, pure “royal” blue, or violetish “midnight” blue. Depending on its source, it sometimes shows white calcite veining, which lowers its value, or golden-looking flecks of the mineral pyrite. The pyrite spangles nestled in the blue bodycolor—like golden stars in a summer sky—produce a unique visual appeal.

Lapis has been mined in Afghanistan for more than 6,000 years. It was trea-sured by the ancient civilizations of Mesopotamia, Egypt, China, Greece, and Rome. Its Latin name literally means “blue stone.” Lapis was considered an emblem of chastity and a cure for sadness. It was also thought to offer protection from evil and ensure the help of angels.

The supply of lapis is plentiful in today’s jewelry mar-ket. Large stones are readily available, and it’s a popular gem material for beads, cabochons, tablets, and carvings. Afghan lapis has always been known for its fine quality and color purity, while lapis mined in Chile often shows less-desirable white veining.

Lapis was dropped from the official US birthstone list in the 1950s, but for many years it was one of the gems for December. You might suggest it as an alternative for customers who were born in that month.

Sources

Afghanistan—Finest quality Chile

Russia

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Stability

Heat High heat can induce an undesirable green color, or cause complete color loss

Light Stable

Chemicals Decomposed slowly by hydrochloric acid; discolored by cyanide solution

Treatments

Treatment Purpose Stability Prevalence Detection Dyeing Common

Common

Care and Cleaning

Ultrasonic cleaning Risky Steam cleaning Never Warm, soapy water Safe

Imitations

Glass Plastic

Alternatives

Improves color and hides white veining

Fair. Some dyes fade or are affected by sol-vents Detectable by a trained gemolo-gist or gemo-logical labora-tory* Coating or impregnation with oil, paraf-fin, or plastic

Improves color and polish appearance; also seals any dye Fair. Treatment (especially oil and paraffin) can be dam-aged or destroyed by heat and chem-icals Detectable by a trained gemol-ogist or gemo-logical labora-tory*

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Malachite

Malachite is an opaque gem with a strong bluish green to green color. It typ-ically shows curved or circular banding (in varying shades of green) that gives it a distinctive beauty. (A closely related gem material, azurmalachite, combines malachite green with the dark blue of the mineral azurite in attrac-tive bands and patterns.)

Malachite has a long history as a gem. One of its main components, and the cause of its color, is copper. It was found along with that metal by early civilizations as they emerged from the Stone Age. The Egyptians used mala-chite for jewelry and other ornamental purposes as early as 4000 Bc. In the

Middle Ages (from about 500 to 1500 AD) people in Europe often hung

malachite on cradles to assure peaceful sleep for their children and protect them from witchcraft. People wore pieces with eye-shaped markings as amulets to ward off the “evil eye.”

Modern jewelry uses for malachite include beads, cabochons, tablets, inlays, and carvings. Its high density gives malachite jewelry such as bead necklaces a weighty feeling that enhances customers’ sense of its value. Because malachite is relatively soft, has poor toughness, and can be attacked by many chemicals, it’s considered an extra-care gem. With proper handling, however, malachite can provide years of pleasure for its wearer.

Sources

Australia Russia United States Zaire

Hardness & Toughness

Hardness 31/₂to 4 on Mohs scale

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Stability

Heat High heat can cause discoloration and damage Light Stable

Chemicals Attacked by acids

Treatments

Treatment Purpose Stability Prevalence Detection Unknown

Care and Cleaning

Imitations

Glass Plastic

Synthetics

Synthetic malachite has been produced on a limited basis. Identification requires advanced testing. (If there is any doubt, send the gem to a gemological

laboratory for verification.)

Alternatives

Agate (dyed green) Jadeite jade Nephrite jade Turquoise Impregnation with paraffin or epoxy resin Intensifies color, improves polish appear-ance, and hides small cracks

Fair. Treatment can be dam-aged or destroyed by heat and chem-icals Detectable by a trained gemol-ogist or gemo-logical labora-tory* Suite of malachite

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Malaya Garnet

Malaya (also spelled malaia) garnet is a relatively new member of the garnet group. Specimens of it first appeared in the 1960s, mixed in with parcels of rhodo-lite garnets from the Umba River Valley of East Africa. At first, buyers rejected the unfamiliar gem material, so local miners and dealers gave it a Swahili name that literally translates “out of the family.”

Tests eventually proved malaya garnet to be a chem-ical mixture of two garnets: pyrope and spessartite. The gem’s lively color—light to dark pinkish, reddish, or yellowish orange—conquered buyer resistance, and during the 1980s it gained a small but strong market, particularly in the US.

Malaya is one of the more expensive garnets. It’s usually available in various fancy shapes up to about 10 cts. Along with the other garnets, it’s a US birthstone for January. In Europe, malaya is known as umbalite, after the region that remains the gem’s only source.

Sources

Kenya Tanzania

Hardness & Toughness

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Stability

Heat Sudden temperature change can cause fracturing

Light Stable

Chemicals Slightly attacked by hydrofluoric acid

Care and Cleaning

Type of Cleaning Advisability Ultrasonic cleaning Usually safe Steam cleaning Never Warm, soapy water Safe

Imitations

Glass Synthetic sapphire Synthetic spinel

Alternatives

Almandite Carnelian Citrine Sapphire Spessartite garnet Spinel Topaz Tourmaline Zircon

Color-change malaya garnets in fluorescent light Color-change 8.51-ct. malaya garnet under incandescent light Color-change 8.51-ct.

malaya garnet under fluorescent light

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Moonstone

_{Moonstone/Orthoclase/Feldspar}

According to Hindu mythology, moonstone is made of solidified moonbeams. Many other cultures also associ-ate this gem with moonlight, and it’s easy to see why. Its internal structure scatters the light that hits it and creates a phenomenon known as adularescence. The visual effect is reminiscent of the full moon shining through a veil of high, thin clouds.

Legends say that moonstone brings good luck. Many believed that you could see the future if you held a moonstone in your mouth during a full moon.

Moonstone ranges from semitransparent to opaque. You’ll most often find it in cabochons and carvings, set in rings and pendants. It’s also popular in bead neck-laces and bracelets. It’s usually colorless, white, or light bluish gray, with white or blue adularescence. Other colors include light green, yellow, brown, and some-times gray to black. The market supply is normally steady in sizes up to about 25 cts., with larger stones available in limited quantities. Along with alexandrite and cultured pearl, moonstone is one of the US birth-stones for June.

Sources

India

Myanmar (Burma) Sri Lanka

Hardness & Toughness

Faceted moonstone with blue adularescence

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Stability

Heat High heat or sudden temperature change can cause breaks

Light Stable

Care and Cleaning

Imitations

Glass Plastic

Alternatives

Milky chalcedony

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Morganite

_{Morganite/Beryl}

In 1911, a transparent gem discovered on the African island of Madagascar was hailed as an exciting new alternative to kunzite and pink tourmaline. The rose pink to lilac gem was named in honor of wealthy banker and gem connoisseur John Pierpont Morgan. Morgan was an avid customer of Tiffany’s, and the jewelry store enthusiastically promoted the gem.

Eventually, Madagascar’s morganite deposits declined and Brazil became the gem’s top producer. Although the gem’s finest color is a deep magenta, most morganites on the market are a pale pink. Many Brazilian morganites emerge from the mines sporting an attractive peach (orange-pink) hue that’s appealing to some buyers. But produc-ers usually heat treat gems of this hue to arrive at a pink shade that’s preferred in the marketplace.

Morganite is a variety of beryl, which makes it a rel-ative of emerald and aquamarine. The gem’s beauty and limited availability make it a favorite of collectors.

Sources

Afghanistan Brazil Madagascar US

Hardness & Toughness

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Stability

Heat Pinkish orange may fade to pink; may fracture if liquid inclusions present

Light Stable

Chemicals Resistant to all acids except hydrofluoric

Treatments

Treatment Purpose Stability Prevalence Detection

Heating Unknown Undetectable

Care and Cleaning

Ultrasonic cleaning Risky if highly included (rare) Steam cleaning Risky if highly included (rare) Warm, soapy water Safe

Alternatives

Kunzite Pink tourmaline Rose quartz Sapphire Spinel Topaz Improves pink color by removing orange tint Stable, except at temperatures over 400°C