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.
Bronzite is a member of the pyroxene group of minerals, belonging with enstatite and hypersthene to the orthorhombic series of the group. The color of bronzite is green or brown; its specific gravity is about 3.3–3.4, varying with the amount of iron present. The refractive indices and optic angle increase with iron content. Bronzite is sometimes cut and polished, usually in convex forms, for small ornamental objects. It often has a more-or-less distinct fibrous structure, and when this is pronounced the sheen has a certain resemblance to that of cats-eye.