CS-6: Treatments Flashcards
Which of these is considered a gem treatment?
a. Cutting
b. Polishing
c. Fashioning
d. Fracture Filling
D. Fracture Filling
Written information on dyeing gems dates back to about: When?
200 BC
Which gem is commonly heat-treated?
a. Iolite
b. Amber
c. Tsavorite
d. Rhodolite
B. Amber
Heat can lighten amethyst’s purple by (how)?
Causng changes in color centers
Creating asterism with heat treatment is most common in (what stone)?
Synthetic Corundum
What coloring agents do treaters use during lattice diffusion to create a shallow layer of blue color in corundum?
Titanium oxide and iron oxide
How deep is the color layer that lattice diffusion with titanium or chromium creates in corundum/
0.01 mm to 0.50 mm
What agent can create a shallow layer of asterism when it’s introduced below the surface of a corundum cabochon by lattice diffusion?
Titanium Oxide
For effective clarity enhancement, the material used to fill a gem’s fractures must have nearly the same (what)?
Refractive index as the gem
After irradiation, which gem’s color is stable under normal wearing conditions?
Golden Beryl
Jadeite is often (what)
Bleached and polymer impregnated
The Zachery method is a treatment applied to (what stone)?
Turquoise
Heat treatment in a reducing environment does what?
Deepens blue color in sapphire
Quartz or topaz with a thin layer of gold deposited on the surface is known as what?
Aqua Aura
Treaters use sugar treatment to enhance what stone?
Opal
Definition:
A treatment that uses chemical to lighten or remove color
Answer:
Bleaching
Definition:
Filling of pores or other openings with melted wax, resin, polymer, or plastic to improve appearance and stability
Answer:
Colorless Impregnation
Definition:
A treatment that adds color or affects color by deepening it, making it more even, or changing it
Answer:
Dyeing
Definition:
Using a filler to concel fractures and improve the apparent clarity of a gem
Answer:
Fracture (fissure) filling
Definition:
A chemical that treaters mix with some resins to cause them to solidify
Answer:
Hardener
Definition:
Exposing a gem to rising temperatures for the purpose of changing its appearance
Answer:
Heat Treatment
Definition:
Exposing a gem to radiation to change or improve its color
Answer:
Irradiation
Definition:
A treatment in which a gem is exposed to high temperatures and chemicals to allow penetration of color-causing elements
Answer:
Lattice Diffusion
Definition:
An oxygen-rich environment that surrounds a gem during heat treatment, causing it to absorb oxygen
Answer:
Oxidizing environment
Definition:
A liquid filling material that’s very durable when it dries
Answer:
Polymer
Definition:
A rapid heating and cooling process that produces fractures in a stone so it will accept dye
Answer:
Quench Crackling
Definition:
A oxygen-poor environment that surrounds a gem during heat treatment, causing it to lose oxygen
Answer:
Reducing environment
Definition:
A clear, viscous substance that’s used to fill fractures in gemstones
Answer:
Resin
Definition:
Heating a wrapped opal until smoke or ash penetrates its surface to darken it and bring out its play-of-color
Answer:
Smoke Treatment
Definition:
Soaking an opal in a hot sugar solution and then in sulfuric acid to darken it and bring out its play-of-color
Answer:
Sugar treatment
Definition:
Altering a gem’s appearance by applying backings, coatings, or coloring agents like paint
Answer:
Surface modification
Definition:
Any human-controlled process, beyond cutting and polishing, that improves the appearance, durability,or value of a gem
Answer:
Treatment
Key Concepts:
What are 2 things that treatments improve increase the supply of commercially important stones?
- Gem Appearance
- Quality
Key Concepts:
What are 6 gems that are commonly heat treated?
- Corundum
- Tanzanite
- Zircon
- Topaz
- Aquamarine
- Amber
Key Concepts:
What are commonly irradiated gems (3)?
- Topaz
- Tourmaline
- Cultured Pearl
Key Concepts:
How is Jadeite often treated?
Combination of
- Bleaching and
- Impregnation
Key Concepts:
What is one of the oldest gem treatments?
Dyeing
Key Concepts:
What are commonly dyed gems (4)?
- Cultured Pearl
- Lapis Lazuli
- Chalcedony
- Coral
