Hi to everybody! Synthetic opal DOES exist, we all must remember the "Mexi-Fire" synthesis, which is NOT an imitation of fire-opal! Recently I was sold a Kyocera opal synthesis in Idar-Oberstein, and the seller declared me it is a rightful synthesis and not an imitation! By microscope I think you just have to compare a natural stone, a synthetic one and an imitation for realizing the difference between one another, otherwise it might be difficult to distinguish them, expecially if you don't see them every day! Greetings from Italy by Riccardo.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
A New Type of Synthetic Fire Opal: Mexifire
Quote:
Abstract
Synthetic opals have been produced and used in jewelry for more than three decades, and various imitation opals have been introduced in the trade. This article describes a new type of synthetic fire opal marketed as "Mexifire." Some of the gemological properties of this synthetic are similar to those of natural fire opal. However, a low SG value (<1.77) offers strong evidence of synthetic origin, and further indications are provided by a relatively low Rl value (<1.40) and the presence of scattered pinpoints when examined with magnification.
Direct Link to Download pdf [pdfview]http://gia.metapress.com/content/y0564520l7714175/fulltext.pdf[/pdfview]
Joined: Tue Oct 20, 2009 3:34 pm Posts: 381 Location: Sweden
Sometimes I wonder WHY I did ask? Maybe I should live in my little bubbletent and just enjoy my gems, and don´t bother if they are real or fake, they are nice to look at anyway!
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
So sorry Lennie for the sidetrack. Some might find the information on Synthetic Fire Opal useful, as it does address the subject of synthetic opal.
Your question was initially how to determine if an opal (not orange fire opal) is synthetic. There is not a great deal in the literature...and I don't know if you clicked through to GemInterest, but it supplies some useful visuals.
-Synthetic opal has a distinctive snakeskin pattern. This may be the most diagnostic feature and does NOT refer to patches of color being snake like: Check out this picture at 45X directly from Geminterest: It actually reflects the columnar character of synthetic opal seen on the surface:
Joined: Mon Oct 17, 2005 10:56 am Posts: 6461 Location: The frozen north prairie :-/
Google "chicken wire" and you'll see the pattern that the columnar structure (not "inclusions" in the usual sense of the word) in synthetic opals is sometimes named for .
_________________ IIJA Registered Gemologist GIA Graduate Gemologist
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