Nephrite's a variety of the calcium and magnesium-rich amphibole mineral actinolite (aggregates of which also make up one form of asbestos). The chemical formula for nephrite's Ca2(Mg,Fe)5Si8O22(OH)2. It's one of two different mineral species called jade. The other mineral species known as jade's jadeite, which's a variety of pyroxene. While nephrite jade possess mainly grays and greens (and occasionally yellows, browns or whites), Jadeite jade, which's rarer, can also contain blacks, reds, pin… (More on Nephrite)