Jasper Jasper Jasper, an aggregate of microgranular quartz and/or chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III) inclusions. The mineral aggregate breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The specific gravity of jasper is typically 2.5 to 2.9. A green variety with red spots, known as heliotrope (bloodstone), is one of the traditional birthstones
Diamond simulant they are easily distinguished by cerussite's high density (SG 6.51) and anisotropy with extreme birefringence (0.271). Due to their rarity fancy-colored diamonds are also imitated, and zircon can serve this purpose too. Applying heat treatment to brown zircon can create several bright colors: these are most commonly sky-blue, golden yellow, and red. Blue zircon is very popular, but it is not necessarily color stable; prolonged exposure to ultraviolet light (including the UV component in sunlight) tends to bleach the stone. Heat treatment also imparts greater brittleness to zircon and characteristic inclusions. Another fragile candidate mineral is sphalerite (zinc blende). Gem-quality