QUIZ 1 Colored Stones

A regular, repeating internal arrangement of aroma in a material is it's

Crystal structure

A synthetic gem and its natural counterpart have essentially the same

Crystal structure

Low cost and high volume characterize which process?

Flame fusion

The district in Brazil that is most famous for it's pegmatite deposit of tourmaline topaz and beryl is

Minas Gerais district, known for it's rich mineral diversity and is a significant source of various gemstones and minerals

which is a key locality for hydrothermal gems?

Ouro Presto, Brazil

Which is a workable alluvial deposit of gem minerals with economic potential?

Placer

Which of the following best describes the fracture of an aggregated mineral like jadeite?

Splintery or Fibrous due to it's compact and interlocking crystal structure

When heat treatment takes place in the presence of gases other than oxygen called

a reducing environment the gem tends to gain electronic

The term "seed crystal" is defined as

a tiny crystal used as the template for gem growth

The term used to describe a gem that is colored by trace elements in its crystal structure is

allochromatic

All doubly refractive gems have at least one singly refractive direction

along the optic axis

An example of an amorphous material is

amber

The relationship of aquamarine to beryl is

aquamarine is a variety of beryl

GIA's position is that a treatment should be disclosed as part of every transaction

even if it's only suspected

The emission of visible light in response to stimulation from a higher energy light, usually X-ray or UV light is called

fluorescence

A treatment that causes he formation of small cracks that accept dye in a gem is called

fracture filling

Common fracture filling substances include oils, reasons polymers and

glass

The characteristic shape of a gem crystal is called its

habit

Lead glass makes a good fracture filling material for Ruby due to it's similar refraction index but it is

important to note that this treatment may affect the durability and long-term stability of the gemstone

A characteristic enclosed within a gemstone is called an

inclusion

In gems, phenomenon caused by structure are the result of the

interaction of light with the internal structure of the gemstone, leading to unique visual effects like iridescence

An organic gem is

made by a living organism

Visual observation of inclusions can help gemological identify a gem as well as indicate it's

natural or synthetic origin

Which of the following gems forms as the result of a sedimentary process

opal

The best display asterism, the cutter fashions a cabochon with it's reflective inclusion

parallel to the base

A quantity of stones of similar or mixed qualities from a single mine or from various sources, offered for sale together is called a

parcel

The biggest and most well-formed crystals are found in

pegmatites

metamorphic rocks are altered by heat and

pressure

The type of deposit that's most likely to be found miles away from the original source rock is

sedimentary deposit

The method used to produce synthetic cubic zirconia (CZ) is

skull melt

Colored Stones are most commonly mined by

small groups of independent miners

The two types of processes for synthetic gem production are melt and

solution

Although it's own gem resources have been declining since the 1960's, Thailand remains a major player in the gem industry for to it's expertise in

tearing and cutting

When crystal growth is interrupted and then resumes again in a different direction, this is called

twinning

Major sales outlets that often see record-breaking process from the sales of fine gems and jewelry are

auction houses

The three basic types of surface modification are coating, painting, and

backing

The concept of reserving a portion of the resources drives from a country for the economic development of the country is called

beneficiation

Which cobalt is present in either synthetic spinel or some fine natural spinel, this produces

blue

The elongated synthetic crystal produced by flame fusion or pulling methods is called

boule

One of the most doubly refractive minerals, which displays eye-visible doubling in transparent material is

calcite

To produce large quantities of identical jewelry pieces for the commercial m market, a manufacturer would need to find a good supplier of

calibrated stones

Treatment that involves wrapping Opals in a carbon rich material such as paper or dried manure and then heating is called

carbon treatment

Heat can lighten amethyst's purple by

causing changes in color centers

To facilitate the healing of fissures during ruby heat treatment, treaters use the presence of

certain fluxes, such as borax or boric acid, which help lower the melting point of the surrounding material into healing process

The kind of relative quantities of aroma that make up a material are defined as it's

chemical composition

A rock must be

composed of masses of many crystals

Most colored stones from the earth's

crust

The crystal system with the highest degree of symmetry is

cubic

You can almost be sure that a gem is synthetic if it's growth marks are

curved

The gem industry sector that Jaipur, India is renound for is

cutting and polishing.. cutting and shaping gemstones to enhance their beauty and value