Spinel is the magnesium aluminum member of the larger spinel group of minerals. Its hardness is 8, its specific gravity is 3.5–4.1, and it is transparent to opaque with a vitreous to dull luster. It may be colorless, but is usually various shades of red, blue, green, yellow, brown, or black.
Gold(14K) A coating of gold is deposited on the item using the galvanic method or IP process. It is mixed with other metals, usually silver or copper, to make it less expensive, harder, and longer lasting while preserving the brilliance of pure gold. 14k gold is 14/24 of pure gold, which is approximately 58.3% pure gold.