Sapphire jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs). Sapphire is the birthstone for September and the gem of the 45th anniversary.
Sapphire This issue appeared as a front-page story in the "Wall Street Journal" on 29 August 1984 in an article by Bill Richards, "Carats and Schticks: Sapphire Marketer Upsets The Gem Industry". Diffusion treatments are used to add impurities to the sapphire to enhance color. Typically beryllium is diffused into a sapphire under very high heat, just below the melting point of the sapphire. Initially ("c." 2000) orange sapphires were created, although now the process has been advanced and many colors of sapphire are often treated with beryllium. The colored layer can be removed when stones chip or are repolished or