Gem garnets in the red-to-violet color range.

Abstract

This article is reported as the first of a series of articles dealing with garnets, especially those used as gems. The stated objective is to provide a viable gemmological classification of this group. This article outlines procedures used and treats red to violet garnets of the almandine-pyrope series. It is concluded that three checks (refractive index, specific gravity, and absorption spectra) provide a good indication of the identity of garnets of this series as being predominantly pyrope, predominantly almandine, or having an approximate 1:1 ratio of the two end-members.-R.V.D.