ABSTRACT
Because of the large price differential that exists between synthetic and natural gems, it is important that the gemmologist is not only able to identify a stone but is also able to determine whether it is a natural or a synthetic material. Gemstone simulants can in general be readily identified as their physical constants differ from those of the gemstone they imitate. In this respect, synthetic spinels (with the exception of the red variety) can also be regarded as simulants as they are mainly used to imitate other gemstones and not natural spinels (these stones are covered in Chapter 17, which deals with the identification of simulants).
