Brass is an alloy of copper and zinc. The proportions of zinc and copper can be varied to create a range of brasses with varying properties. For jewelry, the most commonly used percentages of copper and zinc is 67% and 33%. This mixture helps the brass become stronger and more durable than copper alone, which allows for superb electroplating quality, and thus, it is the perfect combination for fashion jewelry.
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.