Gemstone quality diopside is found in two forms: the black star diopside and the chrome diopside (which includes chromium, giving it a rich green colour). At 5.5–6.5 on the Mohs scale, chrome diopside is relatively soft to scratch. The Mohs scale of hardness does not measure tensile strength or resistance to fracture.
Diopside is said to derive it’s name from the Greek dis, “twice”, and òpsè, “face” in reference to the two ways of orienting the vertical prism and idosmeaning “shape”.
Dopiopside has been known as a gemstone since antiquity. Usually bottle green, brownish green or light green, it may also be colorless, white brown, black or violet depending on the iron deposits. The very bright green crystals are colored with chromium, while the violets ones are colored with manganese. The violet blue crystals are also called violane.