River Basin localities and several of the State Line Kimberlites have been gem in character. As a gem Gemstone quality diopside is found in two forms: black star diopside and chrome diopside (which includes chromium, giving it a rich green color). At 5.5–6.5 on the Mohs scale, chrome diopside is relatively soft to scratch. Due to the deep green color of the gem, they are sometimes referred to as Siberian emeralds, although they are on a gemological level completely unrelated, emerald being a precious stone and diopside being a semi-precious stone. Violane is a manganese-rich variety of diopside, violet to light blue in color. Etymology and history Diopside derives its name from the Greek dis, "twice", and òpsè, "face" in reference to the two ways of orienting the vertical prism. Diopside was discovered and first described about 1800, by Brazilian naturalist Jose Bonifacio de Andrada e Silva. Potential uses Diopside based ceramics and glass-ceramics have potential applications in various technological areas. A diopside based glass-ceramic named 'silceram' was produced by scientists from Imperial College, UK during the 1980s from blast furnace slag and other waste products. They also produced glass-ceramic is a potential structural material. Similarly, diopside based ceramics and glass-ceramics have potential applications in the field of biomaterials, nuclear waste immobilization and sealing materials in solid oxide fuel cells. References S. Carter, C.B. Ponton, R.D. Rawlings, P.S. Rogers, Microstructure, chemistry, elastic properties and internal-friction of silceram glass-ceramics, Journal of Materials Science 23 (1988) 2622-2630. T. Nonami, S. Tsutsumi, Study of diopside ceramics for biomaterials, Journal of Materials Science: Materials in Medicine 10 (1999) 475-479. A. Goel, D.U. Tulyaganov, V.V. Kharton, A.A. Yaremchenko, J.M.F. Ferreira, Electrical behaviour of aluminosilicate glass-ceramic sealants and their interaction with metallic SOFC interconnects, Journal of Power Sources 195 (2010) 522-526. Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., Wiley, pp 403–404, Mindat: Chromian diopside, with locales Webmineral Chrome Diopside on gemstone.org Pyroxene group Magnesium minerals Calcium minerals Inosilicates Monoclinic minerals Minerals in space group 15 Luminescent minerals