The English word is derived from the Spanish term piedra de ijada or "loin stone", from its reputed efficacy in curing ailments of the loins and kidneys. In some countries, jade is more commonly known as 'greenstone'. most Jade is from China or Myanmar it is normally cut into cabochon on flat polished peices due to its toughness to work with. It has a mohls hardness of 6.5-7 and a refractive index of 1.652-1.688