To create a larger or more beautiful stone, a gem may be glued to a less valuable mineral to form a doublet. A colorless piece of beryl could be glued on top of green glass to make an emerald-like doublet of little value. A third layer may be added to make a triplet. When carefully crafted, these fabricated stones are difficult to recognize, especially when they are set in a piece of jewelry.
To read this article — and over 25,000 more — try Kovels Membership FREE for 7 Days
Kovels Knowledge Members get full access to 25,000 articles on antiques and collectibles from 60 years of publication.