Feature Gems & Gemology, Summer 1992, Vol. 28, Issue 2

Dyed Natural Corundum as a Ruby Imitation

The gemological properties of a new ruby imitation, produced by dyeing natural colorless to pale-colored corundum, are described. Microscopic and spectroscopic examination revealed a number of diagnostic features: fluorescence of the dye-containing fissures but not the surrounding corundum, red deposits on the fracture planes, and the absence of a 694-nm (chromium) doublet in the spectrum.