Jasper, from Wikipedia, the free encyclopedia
"Jasper, a form of chalcedony,is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. This mineral breaks with a smooth surface, and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and at one time for snuff boxes...Jasper is basically chert which owes its red color to iron inclusions... The jasper is, along with Heliotrope (bloodstone), one of the traditional birthstones for March. It's also a stone in the Jewish High Priest'sbreastplate, described in Exodus 28.
Etymology and history: The name means "spotted or speckled stone", and is derived via Old French jaspre (variant of Anglo-Norman jaspe) and Latin iaspidem (nom. iaspis)) from Greek ἴασπις iaspis, (feminine noun)from a Semitic language (cf. Hebrew יושפה yushphah, Akkadian yashupu), ultimately from Persian یشپyašp.
Green jasper was used to make bow drills in Mehrgarh between 4th-5th millennium BC.Jasper is known to have been a favorite gem in the ancient world; its name can be traced back in Arabic, Persian, Hebrew, Assyrian, Greek and Latin.On Minoan Crete within present day Greece jasper was carved to produce seals circa 1800 BC based upon archaeological recoveries at the palace of Knossos.
Types: Jasper is an opaque rock of virtually any color stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica rich sediment or volcanic ash. Hydrothermal circulation is generally thought to be required in the formation of jasper.[citation needed]. The classification and naming of jasper presents a challenge. Terms attributed to various well-defined materials includes the geographic locality where it is found, sometimes quite restricted such as "Bruneau" (a canyon) and "Lahontan" (a lake), rivers and even individual mountains, many are fanciful such as "Forest Fire" or "Rainbow", while others are descriptive such as "Autumn", "Porcelain" or "Dalmatian". A few are designated by the country of origin such as a Brown Egyptian or Red African leaving tremendous latitude as to what is called what. Picture jaspers exhibit combinations of patterns (such as banding from flow or depositional patterns (from water or wind, dendritic or color variations) resulting in what appear to be scenes or images, on a cut section. Diffusion from a center produces a distinctive orbicular appearance, i.e., Leopard Skin Jasper, or linear banding from a fracture as seen in Leisegang Jasper. Healed, fragmented rock produces brecciated (broken) jasper. Examples of this can be seen at Llanddwyn Island in Wales."

Orbicular jasper from Wikipedia, the free encyclopedia
"Orbicular jasper from Madagascar Orbicular jasper is a variety of jasper which contains variably-colored orbs or spherical inclusions or zones. In highly silicified rhyolite ortuff, quartz and feldspar crystallize in radial aggregates of needle-like crystals which provide the basis or seed for the orbicular structure seen in this kind of jasper. The material is quite attractive when polished and is used as an ornamental stone or gemstone.Various local or commercial names have been used for the material, such as kinradite, oregonite, owyhee jasper, ocean jasper and poppy-patterned jasper, depending on the source. Poppy-patterned jasper or poppy jasper is the varietal name for material from Morgan Hill, Santa Clara County, California. The trade name ocean jasper is used for a variety found along the intertidal shores of northeastMadagascar. In Nebraska orbicular jasper is found in altered rhyolite beds noted for a variety of jaspers and related agates."