GIA Colored Stones 1 Introduction

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COLORED STONES

Introduction





Table of Contents

Subject Page

What is a Gem? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Atoms and Crystals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Species, Varieties, and Mineral Groups . . . . . . . . . . . . . . . . . . . . . . 10

The Colored Stone Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Production and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Consumer Preferences and Marketing . . . . . . . . . . . . . . . . . . . . . . . 22Treatments and Disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

What’s to Come . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Checking Your Progress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29The Final Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Help Isn’t Far Away . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Key Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31



©

©2002 The Gemological Institute of AmericaAll rights reserved: Protected under the Berne Convention.No part of this work may be copied, reproduced, transferred, ortransmitted in any form or by any means whatsoever without theexpress written permission of GIA.

Printed in the United States.Reprinted 2004, 2006

Revised and updated 2013

Cover photos: (clockwise) Donald Stampfli/AP Wide World Photos, John Parrish/Richard Krementz Gemstones

Facing page: Colored stones, like this exceptional Burmese ruby, entice buyers with their romantic history and captivating beauty.



INTRODUCTION

Colored stones have a special allure. For centuries, they’ve been treasured

by maharajahs, emperors, and kings. They come from some of the world’s

most remote locations, where just a few bold adventurers dare to go.

They’re mined in nearly inaccessible mountains and deserts, far from the

modern world of most jewelry consumers.

Many source countries are politically turbulent. A gem’s supply might

go from a torrent to a trickle overnight if a country’s government changes.

Such changes have dramatic effects on a gem’s price, availability, andpopularity.

Although the Big 3—ruby, sapphire, and emerald—have the strongest

hold on consumers’ imaginations, other enticing gems also compete for

attention in today’s marketplace. Some, like tanzanite and tsavorite,

were unknown until very recently. Others, like spessartite garnet and

cultured freshwater pearl, weren’t widely available until new sources

appeared.

1©2002 GIA. All rights reserved.

Peter Parks/AFP



The study of colored stones is not just about gemology. The economics

of supply and demand are just as important. Today—more than at any time

in the past—the number of new gems and new gem sources makes it

necessary for the people who work with colored stones to be better informed.

In Colored Stone Essentials you learned how to sell colored stones at

the retail level. Colored Stones will take you farther down the supply

chain. This course blends the science of gemology with current product

knowledge and practical trade examples to give you the information you

need for a successful career in the jewelry industry.

2

C O L O R E D S T O N E S 1

August Theodor Schoefft/Christie’s Images Inc.

Gems have been coveted by royalty throughout history. An Indian maharajah displayshis priceless treasure of rubies, emeralds, and pearls (above). The magnificentemerald and diamond jewelry (left) once belonged to Catherine the Great of Russia.

Donald Stampfli/AP Wide World Photos

Welcome to the Colored Stones

course! This course will helpyou build on the knowledgeyou gained in Colored Stone

Essentials. When you’ve success-fully completed the course:

• You’ll have a solid foundationof colored stone knowledge.

• You’ll be able to apply thebasic principles of gemologyto judge the color, clarity, andcut of colored gemstones.

• You’ll be familiar with mostmajor gem treatments.

• You’ll understand the structureof the colored stone industry,

from mining through productionand marketing, up to finalretail sales.

• You’ll qualify for positions such

as gem laboratory staff, salesassociate, assistant buyer, andcustomer service representative.



This course will serve as a guide to the multitude of colored stones in

today’s market. You’ll learn how wholesalers, gem cutters, and miners

judge and market them. You’ll discover which gems are most commer-

cially important and why. You’ll understand the value differences among

gems. You’ll gain insight into the shifting patterns of colored stone supply

and how they affect gem prices and availability.

Whether you work in retail or in the wholesale colored stone industry,

this course will give you the information you need to sell more colored

stones.

3

©Harold and Erica Van Pelt

New sources can increase a gem’s availability and enhance its position in thecolored stone market. Examples are Chinese freshwater pearls (above) and EastAfrican fancy sapphires (top right), which are much more available today.

Tino Hammid/GIA

Michel Viard/AFP

A miner is the first to recognize a coloredstone’s value. Like many gems, thesesapphires were extracted from a remotelocation using primitive mining methods.

INTRODUCTION



WHAT IS A GEM? What are gems made of?

What is a mineral?

How do gemologists classify gems?

Almost all the colored stones you’ll encounter in this course form in theearth. They’re inorganic, which means that they’re composed of—or arisefrom—non-living matter. Some other gems—like pearl, coral, amber, andivory—are produced by living organisms, which means that they’reorganic.

Whether gems form within the earth or from animals or plants, they’rereferred to as natural gems. This distinguishes them from materials produced in a factory or laboratory.

4


Ralph Gabriner/Maija Neimanis

This contemporary necklace features a combination of organic and inorganic gems. The pearls were produced by a livinganimal—a mollusk—while the aquamarines and peridots were derived from non-living matter.

Inorganic —Composed of, orarising from, non-living matter.

Organic —Produced by, or derivedfrom, a living organism.

Natural gems —Gems producedby natural processes, withouthuman help.



ATOMS AND CRYSTALS

All gems—inorganic and organic—are made up of atoms. Atoms are the

basic structural units of matter and the smallest units that retain the

characteristics of a chemical element . Chemical elements consist of only

one kind of atom, and combinations of them make up and color gems.

Chromium atoms, for example, color ruby red, and aluminum and oxygenatoms build its crystals.

The kinds and relative quantities of atoms that make up a material

comprise its chemical composition. Each gem has its own unique chemical

composition. Emerald, for example, is a precise combination of beryllium,

silicon, aluminum, and oxygen atoms.

Knowing about the atoms and their arrangement within a gem will help

you understand its physical properties, right down to the sharpness of its

5

Jeffrey Scovil

Each gem is built from a specific combination of atoms of different types and amounts. This combination is called chemicalcomposition.

Atom—The basic structural unit ofall matter.

Chemical element —A substancethat consists of atoms of only onekind.

Chemical composition—Kinds andrelative quantities of atoms thatmake up a material.

INTRODUCTION



facets and the perfection of its polish. The types of atoms a gem containsand how they’re combined determine everything you see when you look at a gem and how it feels when you handle it.

Almost all the gems used in jewelry are minerals. Minerals are natu-ral, inorganic substances with characteristic chemical compositionand—usually—characteristic structure, too. Synthetic gem materialsaren’t minerals because they’re grown in a laboratory rather than in theearth.

6


Peter Johnston/GIA

Atoms are the basic building blocks of all matter, including crystals. Different kindsof atoms combine in different ways to form gems of all kinds.

KEY

Most gems are minerals.

To be a gem, a mineral must be

beautiful, durable, and rare.

Concepts

atoms

combined atoms

crystal structure

Building a Crystal

crystal



While most gems are minerals, very few minerals qualify as gems. Tobe a gem, a mineral must be beautiful, durable, and rare. These three factors are what make a gem desirable. Of the more than 3,000 mineralsdiscovered so far, only about 100 qualify as gems.

Some gems are rocks, which means they’re made up of masses of mineral crystals. Some rocks, like marble, are composed of crystals of asingle mineral, but most contain more than one kind. An example is lapislazuli, which is made up of the minerals lazulite, calcite, and pyrite.

7

Robert Weldon/GIA

Chromium is the chemical element that gives these rubies their vibrant red hue.

Jeffrey Scovil

Most minerals lack the beauty, durability,and rarity to be gems. Out of the 3,000minerals on earth, only about 100 qualify

as gems. Emerald is one of them.

Robert Weldon/GIA

The mottled gray patches and brassyspecks in these lapis lazuli specimensare the minerals calcite and pyrite. Lapislazuli is classified as a rock because itconsists of more than one mineral.

Mineral —A natural, inorganicsubstance with a characteristicchemical composition and usuallycharacteristic structure.

Rock —A natural material com-posed of masses of mineralcrystals of one or more kinds.

INTRODUCTION



Many of the most common minerals, and virtually all of the rocks nearthe earth’s surface, are silicates, which simply means that they contain the

elements silicon and oxygen. Most quartz gems are composed almostsolely of silicon and oxygen. That’s why the term silica is sometimes usedto describe quartz. The list of gems that are silicates also includes beryl,garnet, tourmaline, jadeite, spodumene, and opal.

Minerals almost always form as crystals. A crystal is solid matterwith atoms arranged in a regular, repeating, three-dimensional patterncalled crystal structure, or crystal lattice. A crystal can be natural ormanmade.

Most transparent gems are cut from one large crystal. Other gems—

8


Robert Weldon/GIA

Many gemstones are silicates, which means they contain a combination of siliconand oxygen. Quartz is one of the simplest silicates because it’s composed almostentirely of those two elements.

Silicate —A mineral that containsthe elements silicon and oxygen.

Crystal structure —Regular,repeating internal arrangement

of atoms in a material.



like turquoise—are made up of many tiny crystals that might not be visible

to the unaided eye. Still others, like lapis lazuli, are made up of mixtures

of different mineral crystals.Many rocks are intergrowths of clearly visible mineral crystals.

Architects choose granite for the facades of many buildings because of thedecorative effect of its differently colored, interlocking crystals.

While the majority of colored stones are crystals, there are some

important exceptions. Fire opal appears to have the same transparency asmany other gems, but it lacks a regular, repeating crystal structure.Gemologists describe gems without a regular crystal structure as amor-

phous. Amber is another amorphous gem material.

9

Jeffrey Scovil

The pattern of a gem’s atoms is called its crystal structure. This tourmaline crystal’sorderly internal structure is reflected externally in its symmetrical shape.

Ted Spiegel/Corbis

Amorphous —Lacking a regularcrystal structure.

INTRODUCTION

Albert J. Copley/PhotoDisc

Amorphous gems, like opal (top) andamber (bottom), lack the orderly crystalstructure that’s found in gems like rubyand emerald.



SPECIES, VARIETIES, AND MINERAL GROUPS

As you learned in Colored Stone Essentials, gemologists divide naturalgem minerals into gem species. A gem species is a broad gem categorybased on chemical composition and crystal structure.

The mineral species beryl, for example, is made up of a regular, repeat-ing structure of beryllium, aluminum, oxygen, and silicon atoms. Thoseatoms—in the proper arrangement and relative quantities—always definethat mineral species. But the broad species name isn’t enough to describe

10


Shane McClure/GIA

Gemologists classify gems into broad categories called species. This suite of roughand cut gems from Sri Lanka includes the gem species spinel, zircon, chrysoberyl,and corundum. Each one has its own chemical composition and crystal structure.

Gem species —A broad gemcategory based on chemicalcomposition and crystal structure.



the wealth of color—glorious greens, blues, pinks, reds, and yellows—of a gem species like beryl.

Gemologists use the term variety to describe these color variations.Variety is a subcategory of species, based on color, transparency, or phenomenon (a phenomenon is a special optical effect, like the star instar sapphire, or the blue sheen in moonstone). In the beryl species, for example, aquamarine is the most widely known blue variety, and emeraldis the highly prized green variety.

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Gem variety —A subcategory ofspecies, based on color, trans-parency, or phenomenon.

INTRODUCTION

Sotheby’s

Zircon is a gem species with many color varieties (right). A zircon is classified by itscolor and species name—blue zircon, green zircon, etc. Peridot (above) is a specieswith a narrow yellowish green to greenish yellow color range, so it has no color-based varieties.

Tino Hammid/GIA



Sometimes, several gem species differ only slightly from each other.

Because they’re so similar, gemologists might classify them as a group. Agroup is a family of closely related mineral species that share the same crys-

tal structure and basic chemistry, but differ slightly in other details. These

differences often lead to differences in physical and optical properties.

There are many mineral groups, but only a few contain important gem

species. The best-known gem groups are garnet, feldspar, and tourmaline.

The important species in the garnet group—almandite, pyrope, spes-

sartite, grossularite, and andradite—share the same crystal structure and

12


Group —A family of gems from

several closely related mineralspecies.

Peter Johnston/GIA

The garnet group is a family of gems with the same crystal structure and the samebasic chemistry of aluminum, silicon, and oxygen. Their differences lie in the otherchemical elements they contain, which give them differing colors and properties.

Understanding Group, Species, and Variety

The garnet group,a family of closelyrelated mineralspecies

Andradite, one ofseveral importantspecies of gemgarnets

Demantoid, thegreen variety ofthe speciesandradite

GROUP

SPECIES

VARIETY



basic chemistry, but they have slight differences in chemical composition.

For example, almandite is rich in iron, while pyrope contains significantamounts of magnesium. You’ll learn more about this in Assignment 24.

A gem’s rarity can be an important part of its value, and that rarity is

very closely related to the way it forms within the earth. For example, the

formation processes that produce red garnets are far more common than

those that produce ruby. Another factor is that some gems contain more

widely available elements than others, so they’re more prevalent. You’ll

learn more about how gems form in Assignment 2.

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Joel Beeson/GIA

Van Rossen/Columbia Gem House

The garnet group includes stones of dramatically different colors, like these strikinggreen (top) and purple (bottom) examples.

INTRODUCTION



A gem’s rarity and beauty affect how it’s marketed. These factors alsoaffect its value. They are just as important to understand as things likecrystal structure and chemical composition.

THE COLORED STONE MARKET

How are mining and marketing different for diamonds andcolored stones?

How does the supply of a gem affect its marketability?

How do treatments impact the sales of certain colored stones?

There’s a greater selection of colored stones available today than everbefore. And new cutting techniques present familiar materials in interest-ing ways. Because there’s more choice, jewelry designers have to catchcustomers’ eyes with distinctive products and designs.

A fine ruby can provide the warmth that a diamond’s icy beauty can’t

match. Even so, diamonds are economically more important than coloredstones.

The US is the world’s largest gem-consuming market, followed closelyby Japan and Europe. In 2010, US domestic consumption of polisheddiamonds exceeded $18 billion. By comparison, the US domestic marketfor natural, unset, non-diamond gems was $542 million—just a fractionof the diamond total. Imports of emeralds, rubies, and sapphires made upthe majority of that figure.

14


Dave G. Houser/Corbis

A gem’s rarity almost always affects its value. Garnets are so plentiful in Wrangell,Alaska, that youngsters unearth the rough crystals and sell them for pennies percarat.



15

John Parrish/Richard Krementz Gemstones

Colored stones are more popular today than ever before. Gems like garnet, rubellite,and tanzanite can act as attention-getting centerstones in contemporary rings (above).Others like citrine, peridot, and moonstone can be combined into colorful bracelets(right) and other jewelry pieces.

John Parrish/AGTA

INTRODUCTION



Part of the reason for the huge economic difference between diamondsand other gems is that diamond is a single gemstone, while the coloredstones category includes many different gems. This makes diamond easierto market. Until very recently, virtually all of the world’s uncut gem- quality diamonds were marketed through one agency, De Beers’ CentralSelling Organisation (CSO)—now called the Diamond Trading Company(DTC). De Beers has spent many millions of dollars on global diamondadvertising for decades. There’s no such single marketing agency for colored stones.

16


Ralph Gabriner/Jane Bohan Inc.

New sources often introduce new gem materials that can be combined in interestingways. A designer combined rose-colored pearls and a rose-cut pink tourmaline with18K gold to create this elegant jewelry suite.



Diamonds are also featured in many more types of jewelry. Even if afine sapphire or emerald forms the centerpiece of a ring, it’s almostalways surrounded by an array of diamonds.

Multinational mining companies invest hundreds of millions of dollarsand take many years to develop diamond mines, but the potential profitsare enormous. The developers of Canada’s Ekati mine spent more than$700 million for development and early operation, but the estimated valueof the diamonds in the ground is more than $8.6 billion dollars.

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Diamond’s enormous popularity isdue in part to De Beers’ widespreadand well-organized promotional efforts.The marketing of colored stones, incomparison, is inconsistent and

underfunded.

Tiffany & Co.

Diamonds are an extremely important part of the jewelry industry. Even colored stone jewelry is often accented with diamonds.

INTRODUCTION



Many diamond deposits are vast enough to sustain mining for decades.For example, the Jwaneng mine in Botswana is essentially a gigantic pit,1.24 mi. (2 km) long, 0.62 mi. (1 km) wide, and 650 ft. (200 m) deep.But it’s the world’s most profitable diamond mine, with more diamondsper ton of ore than any other mine in Africa. Between 1973 and 1997, production from this mine alone amounted to more than a billion dollars.

Because of the size of their potential output, most diamond mines aremassive industrial operations. Mining of this size and scope is almostunknown with colored stones. Most colored-stone mining operations are

18


Peter Essick/Aurora

©Bill Bachman

The enormous scale of Botswana’s Jwaneng diamond mine (left) would overpowerany colored stone operation. Companies invest billions of dollars on elaborate,mechanized systems and heavy equipment (above).

KEYMany colored stones are mined by

independent miners using small-scale

mining methods.

Concepts



small in scale, worked by individual miners who are working to feed theirfamilies and hoping for a chance at a better life.

Also, unlike diamond mines, colored stone deposits can be mined sporadically for centuries or exploited to exhaustion in just a few decades.You’ll learn more about colored stone mining in the next assignment.

Even though they’re not as economically important as diamonds, colored stones generate many billions of dollars worldwide, not only forthe nations that mine and process rough gems, but also the manufacturers,wholesalers, and retailers who turn them into jewelry products and sellthem to consumers.

Since the late 1990s, the best-selling colored stones have been bluesapphire, tanzanite, ruby, emerald, cultured pearl, pink and green tourma-line, fancy sapphire, tsavorite garnet, opal, amethyst, aquamarine, andrhodolite garnet. These gems are more popular than others—like peridot,blue topaz, and zircon—due to a combination of factors. One is theiravailability, in terms of quantities produced. Another factor is their marketability, which often affects, and relies on, consumer preferences.The third factor has to do with treatments and their ethical disclosure.

PRODUCTION AND AVAILABILITY

As you’ve seen, most colored stone mines are small-scale operationsin remote areas, often with outdated technology and machinery. Communications and infrastructure might be poor. In addition, many mining areas have difficult climates and a prevalence of malaria and otherdiseases. These deposits are generally worked feverishly for short periodsof time and then abandoned when they become less profitable or morechallenging to mine.

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Rakotosaona Nirina

Michael Freeman/Corbis

Most colored stone mining operations are primitive, like the corundum minesin Madagascar (right). Individual miners, like these men in Thailand, recover themajority of gems by sifting through mud and gravel in search of treasure (above).

Bellini & Co.

Today, designers create contemporary jewelry that features the most popularcolored stones.

INTRODUCTION



20


Both by Wendy Stone/Odyssey

Colored stone production fluctuates partly because it typically involves small-scalemining in remote locations with poor infrastructure (top). Markets have learned toadapt to the perpetual rise and fall of gem supply (bottom).

Christie’s Images Inc.

The two vibrant rubies in this ring arefrom Mogok, Myanmar, known for pro-ducing the world’s finest rubies. Political

upheaval continues to interrupt supplyof these coveted gems.



These mining practices lead to temporary abundance of a particulargem, followed by a shortage. This fluctuation in supply usually produceswild price swings that make a gem difficult to market.

Politics and changes of government in producer countries can have a

drastic effect on gem production. For centuries, the Mogok region of Myanmar (formerly Burma) was the world’s most important source of fine rubies—known as “Burmese” rubies—that commanded high pricesin upscale jewelry salons and auctions. In the 1960s, a military coup inMyanmar caused this supply to shut down.

Neighboring Thailand also had ruby mines, but the market generallypreferred the bright Burmese rubies to darker Thai rubies. Rapid advancesin heat treatment made Thai ruby attractive, and suddenly Thailand’sample supplies of smaller, cheaper rubies were just what the market needed. Thai ruby supported the industry’s needs for more than twodecades, but by the late 1980s, even those supplies began to run out.

In the meantime, miners found a rich new ruby deposit in Myanmar.This deposit became the most important source of ruby during the 1990s.In the space of thirty years, the world’s premier ruby supplier hadswitched from Myanmar to Thailand and back to Myanmar again.

The Burmese rubies of the 1960s were notably more intense than thedarker, redder ones from Thailand that became so commercially important

in the 1970s and 1980s. When Thai ruby ran out in the early 1990s, dealers

had to change back to Burmese rubies—this time from a different sourcein Myanmar—with subtle differences of their own.

Each time the source changed, colored stone wholesalers and dealershad to educate their customers to accept changes in ruby price, generalappearance, and quality. Because the jewelry industry clings to tradition

21

Both by Michel Viard/AFP

Thailand’s corundum mines were mostly exhausted by the 1990s, but the countryremained a premier corundum cutting and manufacturing center. In Bangkok, workersfashion sapphires (right) and other gems, then set the stones in jewelry (above).

INTRODUCTION

Vincent Pardieu/GIA

New sources, like this sapphire mine inIlakaka, Madagascar, contribute to risinggem supplies worldwide. Rising andfalling supplies affect the gem market in

many ways and at many levels.



and doesn’t accept change very readily, it takes time for wholesalers to get jewelry manufacturers and retailers to accept stones of noticeably differentappearance than the ones they’re used to. This is just one example of howchanges in supply can affect the colored stone market. Consumer demandis another factor.

CONSUMER PREFERENCES AND MARKETING

As you learned in Colored Stone Essentials, ruby, sapphire, and emeraldhave romantic histories that link them to the rich and famous. But other,lesser-known gems might also attract consumers’ imaginations from timeto time.

Gem colors pass in and out of fashion just like clothing colors do. Warmearth colors, russet browns, and peach shades, in gems like citrine andzircon, might be in favor temporarily to complement a season’s fashions.Delicate pastel shades of peridot, aquamarine, and pink tourmaline might

be one year’s favorites, only to be replaced by stronger, bolder primarycolors the following year.

Sometimes, clever marketing can greatly boost a gem’s popularity. Forthis to succeed, the gem must be available in sufficient quantity to market,and it must be sufficiently attractive—or have some special quality—thatconsumers will find desirable. It must also have a name that’s marketableand easy for consumers to remember, or its name must be already wellestablished, like ruby and sapphire.

The history of tanzanite can help you understand the relationshipbetween supply, demand, and marketing. The gem is an attractive bluevariety of zoisite that’s mined in the African country of Tanzania.

22


The Metropolitan Museum of Art/Edward Owen/APWide World Photos

Robert Weldon

Both ruby and emerald have enjoyed steady consumer demand for ages (left).Some lesser-known gems, like this assortment of earth-toned stones (above), passin and out of fashion along with clothing colors and styles.

KEY

An appealing name can make a gem

much easier to sell.

Concepts



An upscale jeweler invented the name tanzanite in the 1960s to marketthe gem as an alternative to fine sapphire. The association with the famous jeweler added status to the gem’s highly marketable name.

Unfortunately, tanzanite had only a single source, so its supply waseasily upset by external events. In the 1970s, the Tanzanian governmenttook over the mines, and supplies declined considerably.

At first, because demand for the gem was still strong, prices rose aswholesalers competed for the diminishing supply. Less tanzanite reachedthe consumer, and retail prices increased sharply. When prices reached acertain level, consumers resisted paying the price, and promotion of thegem stopped. Tanzanite slipped from public awareness and became a gemsought by only a privileged few.

In the 1980s, the Tanzanian government lost control of the tanzanitemining area, and thousands of independent miners swarmed in. Chaotic,illicit mining—unauthorized by the owners of the land—became rampant, and large quantities of small, inexpensive tanzanites were readily available. Supplies of the gem burst back onto the internationalgem market. Previously high prices plummeted in the face of an abundanceof stones.

23

In the 1960s, Tiffany & Co. created a marketing campaign for tanzanite that inspired intense demand for the newly discovered gem.

INTRODUCTION

Ralph Gabriner/Jane Bohan Inc.

Tanzanite prices rise and fall dependingon the gem’s availability. In the 1970s,tanzanites like this 2.00-ct. cushioncut were extremely expensive becauseTanzanian government regulationslimited production.



By the 1990s, supply became more regular and prices stabilized. Thedemand returned as gem marketers embraced tanzanite and promotedtanzanite jewelry enthusiastically. Television home-shopping channelsintroduced tanzanite to millions of US homes.

Then in the late 1990s, tanzanite mining conditions worsened. Suddenrains in 1998 brought catastrophic flooding that drowned many miners inunderground tunnels. This interrupted the gem’s supply once more. You’lllearn more about this event and about other effects on the tanzanite market in Assignment 21.

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Angelique Crown/GIA

Because Merelani Hill, Tanzania, is the only known source of gem-quality tanzanite,the gem’s supply is easily disrupted by floods and other natural disasters.

KEY

Changes that take place in a gem’s

source country can drastically affect its

availability and price.

Concepts



TREATMENTS AND DISCLOSURE

Until fairly recently, the average consumer wasn’t aware that most commonly available gems are treated to make them marketable. If itweren’t for treatments, many gems might be affordable to only thewealthiest consumers. For example, some unappealing white sapphirerough can be turned a beautiful blue by careful heat treatment. Treatmenthas become an important issue for many consumers, and media publicityabout gem treatments can affect the sales of some colored stones.

25

Both by Michel Viard/AFP

Heat treating gemstones to improve their appearance is a widely accepted practice.Thai workers seal sapphires in ceramic pots before plunging them into an oven (top).After treatment, the stones glow from the intense heat (bottom).

INTRODUCTION

KEY

Treatments improve the marketability and

availability of many gems.

Concepts



The emerald market suffered from negative attention in the 1990s when consumerslearned that sellers were not disclosing that most emeralds were treated to improveclarity.

26


Both by Henry A. Hänni

Heat treatment can turn dark, nearly opaque corundum rough (left) into bright,

transparent, valuable rubies (above).



Emerald is an example of the way treatment and public informationissues can affect sales. As you’ll learn in Assignment 15, most emeraldrough is fractured by the stresses of formation and mining. As a result, most

finished emeralds are treated in some way—usually by filling with oils orresins—to improve their apparent clarity. In the late 1990s, emerald treat-ments received the attention of the media, and the negative publicityreduced consumer confidence in that gem.

High-profile court cases and consumer unease about treatmentsaffected emerald sales. In spite of this, gem importers brought about$143 million of cut emeralds into the United States in 2002. And emeraldremains the number one colored stone import into the United States interms of value.

Treatment is just one aspect of the fascinating world of colored stones.And if you approach the topic correctly, it isn’t a barrier to sales. Mostconsumers readily accept gem treatments if they’re ethically disclosedand explained in a positive way.

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Eric Welch/GIA

Gem treatments must be disclosed clearly and ethically to maintain consumer confidence.

KEY

In spite of treatment that’s sometimes

extensive, emerald is the number one

colored stone by value imported into

the US.

Most consumers accept gem treatments

if they’re ethically disclosed and explained

in a positive way.

Concepts

INTRODUCTION



WHAT’S TO COME

How is this course structured?

How can you get the most benefit from this course?

The Colored Stones course is made up of three main sections. Followingthis assignment’s introduction to the world of colored stones,Assignments 2 through 6 show how a gem’s formation affects its rarity

and value and how a gem’s properties affect its value and the way it’s usedin jewelry. You’ll also read about synthetics and imitations and learn howthe marketability of many gems can be transformed by treatment.

Assignments 7 through 11 introduce you to the factors used to judgegems—color, cut, clarity, and carat weight. You’ll discover how gemsreach the marketplace and how the gem business works.

Assignments 12 through 27 cover the major commercial gems in orderof their importance. The assignments cover them all, from the Big 3—

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Eric Welch/GIA

With eLearning, you can complete assignment questionnaires online and get almostimmediate feedback about your progress.



ruby, sapphire, and emerald—and other market basics like cultured pearls,

jadeite, opal, quartz, tanzanite, topaz, tourmaline, and garnet, to lesser-known gems like spodumene and diopside. You’ll also learn which gemcolors the trade prefers and why.

CHECKING YOUR PROGRESS

The questionnaires you’ll complete in Colored Stones are great ways todetermine what you’ve learned and what you might have missed. Thequestionnaires also give GIA an idea of your progress.

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INTRODUCTION

Dave Bartruff/Stock, Boston Inc./PictureQuest

To succeed in the complex colored stone industry, you need product knowledge aswell as an appreciation of the mystical beauty that makes each gem unique.



Another terrific way to check your progress is to take another look atthe Key Terms and Key Concepts at the end of each assignment. If yourun across a term or concept that isn’t clear to you, you can easily turnback to the part of the assignment where it’s discussed in detail. Just look for its mention in the margin.

Now that you’ve finished Assignment 1, complete the first question-naire. It’s important to do the questionnaires as soon as you finish theassignments, while the information is still fresh in your mind. That way,there’s less danger that you’ll forget important facts.

THE FINAL EXAMINATION

There will be a proctored final exam at the end of the course. You mustcomplete each questionnaire with a minimum score of 75 percent in orderto take the final exam. You can schedule your final exam when you’vecompleted and passed all the questionnaires. Then, to receive yourColored Stones

certificate, you must score at least 75 percent on the final.When you reach the end of the course, you can access the final exam

instructions by clicking the link in the left-hand column of the eLearningpage. Make sure you read them carefully. You don’t need to schedule thefinal until you’re nearly finished with the course.

HELP ISN’T FAR AWAY

Your GIA instructor is just a quick email message or phone call away,Monday through Friday. GIA instructors are gemology experts with manyyears of trade experience. They’ll answer your questions, clarify any partsof the text that you’re unsure of, and help you with study hints. You’ll also

get feedback from your instructor in the form of comments that accom-pany the answers to your questionnaires. Save these comments to refer towhen you review for the final exam.

By using all the resources available to you as you progress through thiscourse—and others you might take in the future—you’ll get the most outof your GIA eLearning experience.

Now it’s time to take the next step in your journey through Colored

Stones. Because the way a gem forms has such an impact on its rarity andeventual value, Assignment 2 concentrates on formation and mining.You’ll see why some gems are fairly plentiful—and therefore inexpen-sive—while others are much more rare and costly.

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Taking the GIA Colored Stones programthrough eLearning allows you to learnessential product and market informationin the environment of your choice.



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KEYConcepts

Most gems are minerals.

To be a gem, a mineral must be beautiful, durable, and rare.

Many colored stones are mined by independent miners using

small-scale mining methods.

An appealing name can make a gem much easier to sell.

Changes that take place in a gem’s source country can drastically affect its availability and price.

Treatments improve the marketability and availability of many

gems.

In spite of treatment that’s sometimes extensive, emerald is the

number one colored stone by value imported into the US.

Most consumers accept gem treatments if they’re ethically

disclosed and explained in a positive way.

Amorphous —Lacking a regular crystal structure.

Atom—The basic structural unit of all matter.

Chemical composition—Kinds and relative quantitiesof atoms that make up a material.

Chemical element —A substance that consists ofatoms of only one kind.

Crystal structure —Regular, repeating internalarrangement of atoms in a material.

Gem species —A broad gem category based onchemical composition and crystal structure.

Gem variety —A subcategory of species, based oncolor, transparency, or phenomenon.

Group —A family of gems from several closely relatedmineral species.

Inorganic —Composed of, or arising from, non-livingmatter.

Mineral —A natural, inorganic substance with a char-acteristic chemical composition and usuallycharacteristic structure.

Natural gems —Gems produced by natural processes,without human help.

Organic —Produced by, or derived from, a livingorganism.

Rock —A natural material composed of masses ofmineral crystals of one or more kinds.

Silicate —A mineral that contains the elements siliconand oxygen.

Key Terms

INTRODUCTION



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ASSIGNMENT 1

QUESTIONNAIRE

Each of the questions or incomplete statements below is followed by several possible answers. Choosethe ONE that BEST answers the question or completes the statement. Then place the letter (A, B, C, or D)corresponding to your answer in the blank at the left of the question.

If you’re unsure about any question, go back, review the assignment, and find the correct answer. Whenyou’ve answered all the questions, transfer your answers to the answer sheet.

________1. A gem produced by, or derived from, a living organism is

A. organic.B. synthetic.

C. inorganic.D. manmade.

________2. Which of the following is an organic gem?

A. JadeB. RubyC. AmberD. Tourmaline

________3. A substance that consists of atoms of only one kind is a

A. mineral.

B. unit cell.C. gem species.D. chemical element.

________4. A natural, inorganic substance with a characteristic chemical composition and usuallycharacteristic crystal structure is a(n)

A. atom.B. mineral.C. synthetic.D. chemical element.

IF YOU NEED HELP: Contact your instructor through the GIA Virtual Campus, or call 800-421-7250 toll-free in the US and Canada,or 760-603-4000; after hours you can leave a message.

CONTINUED NEXT PAGE...



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________5. Most gems are

A. rocks.B. organic.

C. minerals.D. synthetic.

________6. A natural material that’s made up of a mass of one or more kinds of mineral crystals is a

A. rock.B. group.C. variety.D. chemical element.

________7. Which of the following is amorphous?

A. Beryl

B. AmberC. GarnetD. Jadeite

________8. A broad gem category based on chemical composition and crystal structure is a

A. rock.B. group.C. gem variety.D. gem species.

________9. Which of the following is a gem variety?

A. BerylB. GarnetC. AndraditeD. Demantoid

________10. Which group does almandite belong to?

A. SpinelB. GarnetC. FeldsparD. Tourmaline

CONTINUED NEXT PAGE...

INTRODUCTION



34


________11. The world’s largest gem-consuming market is

A. Japan.B. Europe.

C. Thailand.D. United States.

________12. Synthetic gem materials

A. are organic.B. are not minerals.C. are usually amorphous.D. are classified as minerals.

________13. To be a gem, a mineral must be beautiful, durable, and

A. rare.

B. colorful.C. transparent.D. lightweight.

________14. Many colored stones are mined by

A. large corporations.B. massive industrial operations.C. mechanized systems and heavy equipment.D. independent miners using small-scale mining methods.

________15. Media attention in the 1990s regarding its treatment reduced consumer confidence in

A. spinel.B. emerald.C. rhodolite.D. tanzanite.



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PHOTO COURTESIES

The Gemological Institute of America gratefully acknowledges the following people and organizationsfor their assistance in gathering or producing some of the images used in this assignment:

Varujan Arslanyan, 3 (top right)Bob Johnson Collection, 7 (top right)

Gary Bowersox, 7 (bottom right)

Cynthia Renée Co., 22 (right)

Mr. Davenport, 7 (left)

Diamond Promotion Service, 17 (right)

Evan Caplan & Co., 10

F. Joseph Kremer, Goldsmith Inc., 15 (right)

Jack Halpern Collection, 6

David Humphrey, 10

Kaiser Gems, 15 (right)

King’s Ransom, 3 (left)

Richard T. Liddicoat, 8

Maija Neimanis, 4

N.D. International, 10

Shades of the Earth, 5

Tiffany & Co., 23 (top)

Traditional Jewelers, 27

Wayne Thompson Collection, 9 (left)



1. Introduction

2. Gemstone Formation and Mining

3. Gems and Their Physical Properties 4. Gems and Light

5. Synthetics and Imitations

6. Treatments

7. The Colored Stone Market

8. Color

9. Cut

10. Clarity

11. Carat Weight and the Gem Business

12. Ruby

13. Blue Sapphire

14. Fancy Sapphire and Phenomenal Corundum

15. Emerald

16. Pearl Formation, Types, and Market

17 . Pearl Value Factors, Processing, and Treatments

18. Jade19. Opal

20. Quartz and Chalcedony

21. Tanzanite, Iolite, Chrysoberyl, and Andalusite

22. Topaz and Beryl

23. Tourmaline, Peridot, and Zircon

24. Garnet and Spinel

25. Lapis Lazuli, Turquoise, and Other Opaque Gems

26. Feldspar, Spodumene, and Diopside

27. Organics and Collectors’ Stones

Documents

GIA Colored Stones 1 Introduction