Foil/Glass Imitation Opal
Photo by YourGemologist
General Information
What color is it?: As you can see above a quick look might fool consumers but experienced jewelers will know the difference almost immediately. Which is why consumers should stay with a professional jeweler when shopping for opals. These cheap imitations are easy to come by and sometime difficult to spot for the untrained.
What is the story behind this gemstone?: Just another gem material for consumers to worry about and gemologists to learn about. This one is made from glass and foil giving a somewhat close opal look if you are not careful.
Here's the rest of the story on this imitation opal......
Chemical: Si02 (silicon....glass)
Formation: The real question is "why" rather than "how"
Crystal System: Amorphous
Unusual Properties: None
RI: Varies
Optical Character: none
Hardness: Varies
Specific Gravity: Did not waste my time.
Special Identification Properties: Foil inserts are product colors which are not normal for opal.
Gemological Identification
Primary Test: Inspection with a 10x loupe and light source
Cabochon
cut foil-filled glass imitation of opal
Same stone under 30X showing distinct foil areas
Secondary Test: None needed if you own a loupe.
With greatest appreciation to:
Synthetic Imitation & Treated Gemstones by Michael O'Donoghue, Butterworth Heinemann, London, 1997, and
Gems Made by Man, Kurt Nassau, Gemological Institute of America, Santa Monica, 1980
Without whose excellent books
on this subject these web pages would not be possible. YourGemologist.com
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