Nephrite is a variety of the calcium, magnesium, and iron-rich amphibole minerals tremolite or actinolite (aggregates of which also make up one form of asbestos). The chemical formula for nephrite is Ca2(Mg, Fe)5Si8O22(OH)2. It is one of two different mineral species called jade. The other mineral species known as jade is jadeite, which is a variety of pyroxene. While nephrite jade possesses mainly grays and greens (and occasionally yellows, browns or whites), jadeite jade, which is rarer, can also contain blacks, reds, pinks and violets. Nephrite jade is an ornamental stone used in carvings, beads, or cabochon cut gemstones. Nephrite is also the official state mineral of Wyoming. Nephrite can be found in a translucent white to very light yellow form which is known in China as mutton fat jade, in an opaque white to very light brown or gray which is known as chicken bone jade, as well as in a variety of green colors. Western Canada is the principal source of modern lapidary nephrite. Nephrite jade was used mostly in pre-1800 China as well as in New Zealand, the Pacific Coast and Atlantic Coasts of North America, Neolithic Europe, and southeast Asia. Name The name nephrite is derived from , which in turn is derived from Greek ; , which means 'kidney stone' and is the Latin and Greek version of the Spanish (the origin of jade and jadeite). Accordingly, nephrite jade was once believed to be a cure for kidney stones. Other names Besides the terms already mentioned, nephrite has the following synonyms and varieties: aotea, axe-stone, B.C. jade, beilstein, kidney stone, , nephrit, nephrita, , New Zealand greenstone, New Zealand jade, spinach jade (dark grayish green), and . Tomb jade or grave jade are names given to ancient burial nephrite pieces that have a brown or chalky white texture as a surface treatment. History Neolithic and Chalcolithic Europe A lot of nephrite tools and amulets are known since the Early Neolithic (7th millennium BC) to the Late Chalcolithic (5th millennium BC) on the Balkans (mainly Bulgaria; also in Greece, Serbia, Croatia) from two or more unknown sources — Balkan "nephrite culture." Such tools are found in the Later Neolithic of Poland (from the most probable local source Jordanów), Sardinia (Italy) (unknown source) and Switzerland (Kostov, 2005; 2013). Single or just a few finds of nephrite artifacts are also reported from some other European countries. Prehistoric and