Jasper , microgranular quartz aggregates and/or calsedon and other mineral phases, are impeccable and impure silica variations, usually red, yellow, brown or green; and rarely blue. The common red color is due to iron inclusion (III). Mineral aggregates rupture with smooth surfaces and used for ornaments or as gems. It can be very smooth and is used for vases, seals, and tobacco boxes. The jasper weight is usually 2.5-2.9. A variety of green with red spots, known as heliotrop (bloodstone), is one of the traditional birthstones for March. Jaspilite is an iron formation rock that often has distinctive jasper bands.
Video Jasper
Etymology and history
Its name means "spotted or speckled stone", and comes from Old French jaspre (variant of Anglo-Norman jaspe ) and Latin iaspidem (nom. iaspis ) from the Greek ?????? iaspis (feminine noun), from Afroasiatic (see Hebrew ???? yashpeh , Akkadian yashupu ).
Jasper Green is used to make a training arc in Mehrgarh between 4 and 5 millennia BC. Jasper is known to be a favorite gem in the ancient world; his name can be traced back in Arabic, Azerbaijani, Persian, Hebrew, Assyrian, Greek and Latin. In Minoan Crete, jasper was carved to produce seals around 1800 BC, as evidenced by archaeological recovery at Knossos castle.
Although the term jasper is now limited to quartz opac, the ancient iaspis is a pretty big see-through stone including nephrite. The ancient jasper in many cases is clearly green, as it is often compared to emeralds and other green objects. Jasper is referred to in Nibelungenlied as clear and green. The jasper from earlier may include a rock that would now be classed as a calcedon, and such emerald jasper may have been similar to modern chrysoprase. The Hebrew word may have pointed green jasper. Flinders Petrie suggests that the odem , the first stone on the High Priest's chest cover, is a red jasper, while tarsis , the tenth stone, is probably a yellow jasper.
Maps Jasper
Type
Jasper is an opaque stone of almost any color derived from the mineral content of the original sediment or ash. Patterns arise during the consolidation process forming streams and settling patterns in the original silica-rich sediments or volcanic ash. Hydrothermal circulation is generally considered necessary in jasper formation.
Jasper can be modified by mineral diffusion along the discontinuity giving the appearance of vegetative growth, ie dendritic. The original material is often cracked and/or distorted, after deposition, into various patterns, which are then filled with other colored minerals. Weathering, with time, will create a very strong superficial skin.
The classification and naming of jasper varieties presents a challenge. Terms associated with well-defined materials include the geographical area in which it is found, sometimes very limited as "Bruneau" (canyon) and "Lahontan" (lake), river and even individual mountain; many imaginary, such as "forest fires" or "rainbows", while others are descriptive, such as "autumn" or "porcelain". Some are designated by places of origin such as Egyptian chocolate or red Africa.
The banded iron formation
Jasper is a major component in the silica-rich parts of bonded iron formations (BIFs) that exhibit low, but present, the amount of oxygen dissolved in water as during the Great Oxidation Event or the snowball of the earth. The red tape, usually more competent than the surrounding hematite layer, is made of microcrystalline red, also called jasper.
Picture jasper
The jaspers picture shows a combination of patterns (such as streams or settling patterns (from water or wind), dendritic or color variations} producing what appears to be scenes or images (on the cut section). Diffusion from the center produces a distinctive orbicular appearance, ie leopard skin jasper, or linear appeal of a fracture as seen in jasper leisegang. Healed and fragmented stones produce broken jasper (broken).
While this "jasper image" can be found all over the world, the color or the special pattern is unique, based on the geographical region where they came from. Biggs jasper Oregon, and the Bruneau jasper from Bruneau Canyon near the Bruneau River in Idaho are known as excellent examples. Another example can be seen at Llanddwyn Island in Wales.
Basanite
Basanite , lydian stone , or lydite is a variety of black or cherty New England jasper. They have been used as test stones in testing the purity of precious metal alloys.
Gallery
See also
- Carnelian
- Jasperware
References
External links
- Ã, "Jasper". Encyclopedia Americana . 1920.
Source of the article : Wikipedia
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