Induced fingerprints.

Abstract

Over the past few years, numerous Verneuil-type (flame fusion) synthetic sapphires and rubies with somewhat natural-appearing induced fingerprint inclusions have surfaced in the trade. This article reports the results of a series of experiments conducted to explain the phenomenon of induced fingerprints and how they are produced in gemstones generally and in flame-fusion synthetic corundum specifically. A simple experiment is described for inducing fingerprint inclusions. -R.V.D.