GIA Colored Stones Exam 651-700 Flashcards Preview

Colored Stones Exam > GIA Colored Stones Exam 651-700 > Flashcards

Flashcards in GIA Colored Stones Exam 651-700 Deck (50)
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1
Q

Heating wrapped opal until smoke or ash penetrates its surface to darken it and bring out its play_of_color is called ____________.

A

smoke treatment

2
Q

Soaking an opal in a hot sugar solution and then in sulfuric acid to darken it and bring our its play_of_color is called ___________.

A

sugar treatment

3
Q

Altering a gem’s appearance by applying backings; coatings or coloring agents like paint is called ___________.

A

surface modification

4
Q

What are the most commonly heat treated gemstones?

A

corundum; zircon; topaz; tanzanite; aquamarine; amber

5
Q

Heat treatment can alter color and create or eliminate ____________ and ___________.

A

phenomena; inclusions

6
Q

Lattice diffusion with titanium produces what?

A

a shallow layer that can be removed with minor polishing.

7
Q

Lattice diffusion with what element may penetrate the entire stone?

A

beryllium

8
Q

Almost all emeralds on the market today are what?

A

fracture filled

9
Q

Common irradiated gems include ____________.

A

topaz; tourmaline; cultured pearl

10
Q

What is one of the oldest gem treatments?

A

dyeing

11
Q

Commonly dyed gems include _______________.

A

cultured pearl; chalcedony; coral; lapis; lazuli

12
Q

A characteristic or irregularity confined to the surface of a polished gemstone is called a ___________.

A

blemish

13
Q

An angular; hollow space that resembles a mineral inclusion is called a ______________

A

negative crystal

14
Q

A general term for a break in a stone is called a ____________.

A

feather

15
Q

An inclusion with the most negative impact on a colored stone’s clarity would be located where?

A

under the table

16
Q

Which colored stone clarity type are the gems usually eye_clean?

A

Type I

17
Q

The highest clarity grade for colored stones is ___________.

A

eye_clean

18
Q

The term “silk” describes _____________.

A

a group of fine needle_like inclusions

19
Q

Fingerprints are considered what?

A

fractures

20
Q

What gems would be classified as Type III?

A

emerald; red beryl; watermelon tourmaline

21
Q

In which colored stone clarity grades do the definitions vary for each clarity type?

A

moderately included

22
Q

What clarity characteristic would usually have the greatest impact on a gem’s marketability?

A

a large unhealed feather

23
Q

Gems that are usually eye_clean include ___________.

A

spodumene; yellow beryl; aquamarine

24
Q

Inclusions are important to gemologists because they do what?

A

help seperate natural from synthetic gems

25
Q

Growth zoning in a colored stone is evidence of what?

A

crystal growth

26
Q

Two factors that determine an inclusion’s impact on a gem’s value are __________ and___________.

A

crystal system and size

27
Q

Tiny nicks and pits caused by wear and damage to a gem’s facet edges or culet is called an ___________.

A

abrasion

28
Q

An opening that extends into a gem from the surface is called a ___________.

A

cavity

29
Q

A damaged area of a gem; usually near a girdle is called a ____________.

A

chip

30
Q

Any hazy or milky area that cannot be described as a feather; fingerprint; or group of included crystals or needles is called a ____________.

A

cloud

31
Q

A long; thin inclusion that can be a solid crystal or a hollow tube that might be filled with liquid or gas is called a _____________.

A

needle

32
Q

Minute inclusion enclosed within a gem; can occur singly or in groups called clouds is called a _____________.

A

pinpoint

33
Q

Contrast between an inclusion and its host gem is called ___________.

A

relief

34
Q

A group of fine needle_like inclusions is called ____________.

A

silk

35
Q

What are the five factors that determine influence of clarity characteristics on marketability?

A

nature; size; number; position and relief

36
Q

Most gems are __________.

A

minerals

37
Q

To be a gem a mineral must be what?

A

beautiful; durable; rare

38
Q

What is the number one stone by value imported into the US?

A

emerald

39
Q

Lacking a crystal structure.

A

amorphous

40
Q

The basic structural element of all matter.

A

atom

41
Q

A substance that consists of atoms of only one kind.

A

chemical element

42
Q

Regular; repeating internal arrangement of atoms in a material is called its ___________.

A

crystal structure

43
Q

A broad gem category based on chemical compostition and crystal structure is called __________.

A

gem species

44
Q

A subcategory of species; based on color; transparency or phenomenon is called a ___________.

A

gem variety

45
Q

A family of gems from several closely related mineral species is called a ______________.

A

group

46
Q

Composed of; or arising from; non_living matter is considered ________.

A

inorganic

47
Q

A natural; inorganic substance with a characteristic chemical composition and usually characteristic structure is called a __________.

A

mineral

48
Q

Produced by; or derived from; a living organism is called ____________.

A

organic

49
Q

A natural material composed of masses of mineral crystals of one or more kinds is called a _________.

A

rock

50
Q

A mineral that contains the elements silicon and oxygen is called a __________.

A

silicate