NEPHRITE
Nephrite is a type of amphibole mineral that is rich in calcium, magnesium, and iron. Nephrite is one of two rocks known as jade, the other being jadeitite (jadeite jade). Both are exceedingly robust and resistant to fracture, and have been used to make choppers and blades since the Neolithic period. The chemical formula for nephrite is Ca2(Mg, Fe)5Si8O22(OH)2.
Along with amphibole, nephrite may contain minor to trace amounts of diopside, grossularitic garnet, magnetite, chromite, graphite, apatite, rutile, pyrite, datolite, vesuvianite, prehnite, talc, serpentine polymorphs, and titanite.
Nephrite is found in a translucent white to very light yellow form known as mutton fat jade in China, an opaque white to very light brown or gray form known as chicken bone jade in China, and a variety of green colours.
