When you are purchasing gemstone jewellery you may sometimes come across the word doublet, or triplet. The seller should explain to you what this means, but I’ve noticed that this isn’t always happening, and only a lightning-quick run through of the term is given, if at all.
Doublets and triplet gemstones aren’t fake gemstones, but they aren’t solid gemstones either. They are a mixture of both genuine gemstone and man-made materials.
A doublet is a genuine gemstone which has been thinly sliced and glued on top of another material such as glass. It’s done mainly to make use of small flat pieces of gemstone (opals especially), and to save money.
A triplet is similar to a doublet, however the triplet also has a clear protective ‘cover’ glued over the gemstone (usually made from glass or clear cheaper gemstone, or even plastic). Some gemstones such as ammolite or black opal are so soft that triplets are the most effective way to set some specimens into jewellery. Though be a little wary with black opal doublets/ triplets – they are sometimes inexpensive white or clear opals set onto a black backing of glass.
The website www.opalsdownunder.com has a fantastic page on the subject, with some good photos to help you identify a doublet/ triplet gemstone.