Feature
Gems & Gemology, Summer 1992, Vol. 28, Issue 2
Dyed Natural Corundum as a Ruby Imitation
K. Schmetzer, H. A. Hänni, E. P. Jegge, and E-J. Schupp
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.
