Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GIA Graduate Gemologist - GEM 220 - Colored Stones > Assignment 6 - Treatments > Flashcards

Assignment 6 - Treatments Flashcards

1
Q

Why are some gems treated?

A

Gems are treated for a number of reasons. Treatments can:
- Deepen, change, or remove color
- Improve clarity
- Create or accentuate phenomena and desirable inclusions
- Improve luster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does treatment affect value?

A
  • Treatments can make gemstones more appealing and dramatically increase their value.
  • But the absence of treatment makes many stones more valuable than treated stones of similar apparent quality.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is treatment disclosure important?

A

Because it affects the value and in some cases the durability.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Any human-controlled process, beyond cutting and polishing, that improves the appearance,
durability, or value of a gem.

A

Treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the most common treatments?

A
  • Heat Treatment
  • Lattice Diffusion
  • Glass Filling
  • Irradiation
  • Bleaching
  • Dyeing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What stones are commonly heat-treated?

A

Commonly heat-treated gems include corundum, tanzanite, zircon, topaz, aquamarine, and amber.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What stones are commonly irradiated?

A

Commonly irradiated gems include topaz, tourmaline, and cultured pearl.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What gems are commonly bleached?

A

Bleaching is a fairly common pearl treatment.

Jadeite is often treated with a combination of bleaching and impregnation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What stones are commonly dyed?

A

Commonly dyed gems include cultured
pearl, lapis lazuli, chalcedony, and coral.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How durable are some gem treatments?

A

Some treatments like heat-treatments are permanent, other are not.

Irradiated color is not always stable, and
exposure to heat or light can destroy it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Exposing a gem to rising temperatures for the purpose of changing its appearance.

A

Heat treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

An oxygen-rich environment that surrounds a gem during heat treatment, causing certain color-causing trace elements to lose electrons.

A

Oxidizing environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A compound that can dissolve another compound at a lower temperature than its own melting point.

A

Flux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Heat treatment in the
presence of a flux that results in the
sealing of a fracture or cavity.

A

Flux healing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A treatment in which a gem is exposed to high
temperatures and chemicals to allow penetration of color-causing elements.

A

Lattice diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can you treat dark blue sapphire?

A

A combination of beryllium diffusion
and heat treatment can improve color in
some dark blue sapphires and make
them more marketable.

17
Q

How deep does Lattice Diffusion penetrate a stone?

A

Lattice diffusion with heavier elements
like titanium and chromium produces a
shallow layer of color that might be
removed by minor repolishing.

The color resulting from lattice diffusion
with beryllium can penetrate the entire
stone.

18
Q

A clear, viscous substance that’s
used to fill fractures in gemstones.

A

Resin

19
Q

A liquid filling material
that’s very durable when it dries.

A

Polymer

20
Q

A chemical that treaters
mix with some resins to cause them
to solidify.

A

Hardener

21
Q

What is the most common treatment of emeralds?

A

Today, almost all emeralds on the market
are subjected to clarity enhancement.

Fracture filling is the most common
form of clarity enhancement.

22
Q

Treatment that improves the apparent clarity of a gem with a colorless or near-colorless filler.

A

Clarity enhancement

23
Q

Use of a colorless to near-colorless filler to conceal fractures and improve the apparent clarity of a gem.

A

Fracture (fissure) filling, as clarity enhancement

24
Q

A treatment that adds color or affects color by deepening it, making it more even, or changing it.

A

Dyeing

25
Q

A rapid heating and cooling process that produces fractures in a stone so it will accept
dye.

A

Quench crackling

26
Q

Altering a gem’s appearance by applying backings, coatings, or coloring agents like paint.

A

Surface modification

27
Q

Soaking an opal in a hot sugar solution and then in sulfuric acid to darken it and bring out its play-of-color.

A

Sugar treatment

28
Q

Heating a wrapped opal until smoke or ash
penetrates its surface to darken it and bring out its play-of-color.

A

Smoke treatment

29
Q

Written information on dyeing gems dates back to about

A. 200 BC.

B. 100 AD.

C. 300 AD.

D.700 AD.

A

A. 200 BC.

30
Q

After irradiation, which gem’s color is stable under normal wearing conditions?

A. Golden beryl

B. Orange sapphire

C. Yellow sapphire

D. Green spodumene

A

A. Golden beryl

31
Q

For effective clarity enhancement, the material used to fill a gem’s fractures must have nearly the same

A. color as the gem.

B. density as the gem.

C. hardness as the gem.

D. refractive index as the gem.

A

D. refractive index as the gem.

32
Q

What agent can create a shallow layer of asterism when it’s introduced below the surface of a corundum cabochon by lattice diffusion?

A. Iron oxide

B. Chromium

C. Titanium oxide

D. Aluminum oxide

A

C. Titanium oxide

33
Q

Quartz or topaz with a thin layer of gold deposited on the surface is known as

A. lemon.

B. smoky.

C. Madeira.

D. aqua aura.

A

D. aqua aura.

34
Q

How deep is the color layer that lattice diffusion with titanium or chromium creates in corundum?

A. 0.01 to 0.50 mm

B. 0.50 to 1.00 mm

C. 1.00 to 1.50 mm

D. 1.50 to 2.00 mm

A

A. 0.01 to 0.50 mm

35
Q

Creating asterism with heat treatment is most common in

A. natural ruby.

B. natural sapphire.

C. synthetic corundum.

D. natural fancy sapphire.

A

C. synthetic corundum.

36
Q

Heat can lighten amethyst’s purple by

A. dissolving rutile.

B. affecting titanium impurities.

C. affecting chromium impurities.

D. causing changes in color centers.

A

D. causing changes in color centers.

GIA Graduate Gemologist - GEM 220 - Colored Stones (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions