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.
Logan Sapphire in total, 16 carats (3.2 g). It is currently on display at the National Museum of Natural History in Washington, D.C., alongside the Bismarck Sapphire Necklace and the Hall Sapphire and Diamond Necklace. Logan Sapphire The Logan Sapphire is a flawless specimen from Sri Lanka, a cushion-cut stone which possesses a rich deep blue color and is the second largest (blue) sapphire known, weighing 422.99 carats (84.6 g). The cushion-cut stone is one of the world's largest and most famous sapphires (its size about that of an egg) that was cut from a crystal mined in Sri Lanka. The Logan