Nephrite is a variety of the calcium an magnesium rich amphibole mineral 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 possess 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.