Minerals and Metals in Ancient India v2.c47.47

v2.c47.47

*Diamond* : Pure carbon C. Hardness 10 in Moh’s Scale (highest). Harder and heavier (sp. gr. 3.52) than quartz. Luster adamantine to greasy. Colour white or sometimes yellow, blue due to impurities. High refractive index. Sometimes shows phosphorescence when rubbed. When full of flaws, used chiefly as abrasive. If flawless, used as gem. Weighed in carats (0.2 g).