Feature
Gems & Gemology, Fall 1995, Vol. 31, No. 3
“Ti-Sapphire”: Czochralski-Pulled Synthetic Pink Sapphire from Union Carbide
Mary L. Johnson, Meredith E. Mercer, Emmanuel Fritsch, Patricia Maddison, and James E. Shigley
One of the most interesting of the commercially available Czochralski pulled synthetic corundums is pink “Ti-sapphire.” This material owes its pleasant, somewhat orangy pink color to trivalent titanium, a common trace element in natural sapphires and rubies that occurs here in an unusual oxidation state. Although most of the gemological features are typical of Czochralski-pulled corundum (gas bubbles or small "pinpoint” inclusions, color zoning), these synthetic sapphires have distinctive fluorescence and optical spectra. These properties are also due to the chromophore Ti3+.
