Though this stone is not very hard (its hardness is from 5 to 6,5 Moh’s Scale depending on the deposit), nephrite is one of the toughest gem minerals known because of the intergrown nature of the individual crystals. There is a story that a big boulder of Siberian nephrite was put once on the anvil and hit by the heavy steam hammer. The boulder did not get a scratch, though the anvil was broken in pieces.
Nephrite gets its name from the Greek “nephros” which means “kidney”, ancient people believed nephrite to treat kidney diseases. Numerous deposits of this material are spread around the world, there are mines in British Columbia (Canada), in China, Australia, New Zealand, Taiwan, and Alaska. Nephrite can have all shades of green color – apple-green, grass-green, olive, sometimes bluish or yellowish. There is also white nephrite, but pure white color is very rare.
The history of nephrite in Russia begins in the 15th century when it was brought from Central Asia by merchants. The first nephrite mine in Russia, in the Sayany mountains near the Baikal lake, was found only in the 18th century. Several varieties of Russian nephrite are really unique – for example, there is the so-called Ulan-hodinskiy nephrite, which has a color much similar to chrysoprase. Sometimes Russian nephrite has a cat’s eye effect, and this in combination with the beautiful green color makes it even more attractive. However, a really good cat’s eye nephrite is very rare, and it is much more expensive than the regular one.