Tanzanite and Other Gems Set With Colored Adhesive
In March 2010, goldsmith Ed Barker (Artistry in Gold, Yountville, California) let GIA know about various gemstones he had encountered in bezel-set rings that were mounted with colored glue. He purchased the rings during 2009 from a customer who had obtained them from a TV shopping network. When Mr. Barker removed the stones from their mountings, he noted that an adhesive -- colored to enhance the appearance of the ruby, amethyst, or tanzanite gems -- was present along the bezel area.
Mr. Barker sent one of the stones, a 1.87 ct tanzanite, to GIA for examination. A purple-colored flexible adhesive was visible on some of the crown facets, particularly at the corners. After it was removed, the color of the tanzanite appeared very slightly lighter. Mr. Barker indicated that the other stones he removed from the rings became noticeably lighter (particularly the amethyst) without the adhesive.
The colored adhesive was obviously intended to enhance the appearance of the stones, as well as help hold them in their mountings. Buyer beware!
- Brendan M. Laurs
GIA Carlsbad
From August 2010 G & G eBrief to me.
Last updated on November 18, 2010 by Francis M Lynch