The "Type" Classification System of Diamonds and Its Importance in Gemology

mond growth, color (e.g., figure 1), and response to laboratory treatments. With the increasing availability of treated and synthetic diamonds in the marketplace, gemologists will benefit from a more complete understanding of diamond type and of the value this information holds for diamond identification. Considerable scientific work has been done on this topic, although citing every reference is beyond the scope of this article (see, e.g., Robertson et al., 1934, 1936; and Kaiser and Bond, 1959). Brief gemological discussions of diamond types appeared in Shigley et al. (1986), Fritsch and Scarratt (1992), and Smith et al. (2000), and more-detailed descriptions were given in Wilks and Wilks (1991) and Collins (2001). Nevertheless, repeated inquiries received at GIA indicate that many practicing gemologists do not have a clear understanding of the basics of diamond type. This article offers a readily accessible, gemology-specific guide to diamond type and related THE “TYPE” CLASSIFICATION SYSTEM OF DIAMONDS AND ITS IMPORTANCE IN GEMOLOGY