Triplet Opals – are a composition of three pieces where a thin slice of natural opal cemented between a dark base material and a transparent top layer (usually of quartz or glass).
A triplet opal is not a solid opal: triplets are made of three pieces, rather like a sandwich. Firstly, a flat thin slice of precious opal is glued on to a backing of common opal, glass or porcelain that has first been darkened. A protective dome of clear quartz crystal is then cemented to the precious opal with a clear resin (glue) to complete the triplet opal. A doublet opal is more valuable than a triplet because it has a greater opal content.