Abraded facet junctions on an untreated Sri Lanka sapphire. According to Robert Webster’s “Gems” (1st edition, 1962, p. 66): “Corundum is a hard stone, indeed the impure material is used as an abrasive, and is rated 9 on the scale of hardness devised by F. Mohs. Despite the hardness of the mineral, however, ruby and sapphire need to be handled with some care, for they are to a slight extent brittle and if dropped on a hard surface or given a sharp blow tend to develop internal flaws and cracks.”
Natural Sapphire • Sri Lanka (Ceylon) • Enhancements: None Detected (None) • Lighting Conditions: Diffuse Overhead
Photographer: E. Billie Hughes •
Image Number: R-003-2383-1 • Date Posted: 28 January 2019
Webster, Robert (1962) Gems: Their Sources, Descriptions and Identification. London: Butterworths, 792 pp., RWHL*