Jade is an ornamental rock. The term jade is applied to two different metamorphic rocks that are composed of different silicate minerals: nephrite and jadeite. Nephrite and jadeite were used from prehistoric periods for hardstone carving. Jadeite has about the same hardness as quartz. Nephrite is slightly softer, but is tougher (more resistant to breakage) than jadeite.
Brown A brown coating gives a piece of jewelry the color of chocolate (dark) or coffee (light) brown. This color of plating is not commonly seen in jewelry, and presents unique and exclusive statement pieces.