An assembled gem (also called a composite gem)[1] is a gemstone made up of other smaller gems.[2] An assembled gem can often be a fake gem with a desirable piece of gemstone attached to pieces of inexpensive imitation gemstones.[3] For example, a combination of a thin layer of green glass and a colorless piece of quartz would be a composite gem.[4]
A doublet is a type of assembled gem which is composed of two parts. A false doublet is a doublet which is a glass piece that looks like a real gem and a real gem that have been attached to look like a larger gem. A triplet is a type of assembled gem composed of three distinct parts.[5]