Jade is an umbrella term for two different types of decorative rocks used for jewelry or ornaments. Jade is often referred to by either of two different silicate mineral names: nephrite, or jadeite. Nephrite is typically green, although may be yellow, white or black. Jadeite varies from white or near-colorless, through various shades of green, to lavender, yellow, orange, brown and black. Rarely it may be blue. However these names are mineralogically incorrect. Both the amphibole jade (nephrite) and pyroxene jade are actually mineral aggregates (rocks) rather than mineral species and thus should not be described by mineral species names. Nephrite was deprecated by the International Mineralogical Association as a mineral species name in 1978. This makes the name "nephrite" mineralogically correct for referring to the rock. As for jadeite, since this is a legitimate mineral species, its name should not be used for the pyroxene jade rock. In China, the name jadeite has been replaced with fei cui, the traditional Chinese name for this gem that was in use long before Damour created the name in 1863.

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, black 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.