19 Questions
What causes the wide variety of colors in topaz?
Color centers and traces of chromium
What is the most rare and valuable variety of topaz?
Imperial, red and pink topaz
What is the main purpose of heat treatment in Aquamarine?
To remove the yellow color component, to produce a more marketable blue
What is the leading producer of aquamarine?
All of the above
Why does topaz require special care in cutting, mounting, polishing and wearing?
Because of its cleavage
What is the definition of imperial topaz?
A widely used trade term for gem-quality topaz of medium reddish orange to orange-red color
What is the world's only known source of red beryl?
Utah, USA
What is the purpose of heating yellow to reddish brown topaz?
To produce a pink color
What is a common morganite treatment process?
Almost always heated, or irradiated first and then heated, to produce or improve the pink color
What is the major commercial source of imperial and red topaz?
The Ouro Preto area of Brazil
What is the trade term for orange-to-yellow and brown topaz ?
Precious Topaz
What distinguishes green beryl from emerald ?
Tone and Saturation levels
What is the trace element of red beryl ?
Manganese
What is the common color of Topaz ?
Colorless
Common Topaz treatments are...?
Heating or a combination of heating and irradiation
In what state does aquamarine shows its finest, most saturated color?
Large Sizes
Due to its crystal structure, what cut(s) is common for topaz ?
Long Ovals, Pearls or Emerald Cut
The finest Aquamarines are ...?
Moderately Strong, medium-dark blue to slightly greenish blue
What are the most important factors for buyers of treated blue topaz ?
Price and uniformity
Study Notes
Topaz
- Red and pink topaz varieties, including imperial topaz, are the most rare and valuable.
- Color centers and traces of chromium cause the wide variety of colors in topaz.
- Topaz crystals are often cut as long ovals, pears, or emerald cuts due to their elongated shape.
- Topaz requires special care in cutting, polishing, mounting, and wear due to its cleavage.
Treatment of Topaz
- Virtually all topaz is treated to produce a blue color.
- Treatment involves heating or a combination of heating and irradiation.
Aquamarine
- The finest aquamarines are a moderately strong, medium-dark blue to slightly greenish blue.
- Brazil, Pakistan, and China are leading producers of aquamarine.
- Virtually all aquamarine is heat-treated to remove the yellow color component and produce a more marketable blue color.
Imperial Topaz
- The definitions of imperial topaz can vary widely.
- The Ouro Preto area of Brazil is the world’s major commercial source of imperial and red topaz.
Other Beryls
- Morganite is almost always heated, or irradiated first and then heated, to produce or improve the pink color.
- Traces of manganese cause red beryl’s color.
- The US state of Utah is the world’s only known source of red beryl.
- Tone and saturation levels distinguish green beryl from emerald.
Key Terms
- Imperial topaz: A widely used trade term for gem-quality topaz of medium reddish orange to orange-red color.
- Precious topaz: A trade term for orange-to-yellow and brown topaz.
This quiz covers various types of colored stones, including topaz and aquamarine, their characteristics, and features that affect their value.
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