jasper

Jasper, an aggregate of microgranular quartz and/or cryptocrystalline 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. Jasper 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 density of jasper is typically 2.5 to 2.9 g/cm3. Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.

==Etymology and history== upright|thumb|Movable Egyptian ring in green jasper and gold, from 664 to 322 BC or later (Late Period), the Walters Art Museum thumb|upright|left|Amulet of scarlet jasper, provenance unknown, [[Royal Pump Room, Harrogate]] thumb|upright|left|Relief|Low-relief sphinx pendant, red jasper, pearl and enamel, French, circa 1870 The name means "spotted or speckled stone," and is derived via Old French (variant of Anglo-Norman jaspe) and Latin (nom. ) from Greek iaspis (feminine noun), from an Afroasiatic language (cf. Hebrew '' , Akkadian yashupu). This Semitic etymology is believed to be unrelated to that of the English given name Jasper, which is of Persian origin, though the Persian word for the mineral jasper is also yashum (یَشم).