Jasper CatgorieIX: silicates
Polished jasper
General
Category	Tectosilicate
Empirical formula	SiO 2
Identification
Color	blkanc, beige, road, green, brown or pink
Crystal system	Trigonal
Bravais lattice	microcrystalline very fractured, cryptocrystalline
Cleavage	no
Fracture	conchoidal
Mohs	6,5-7
Brightness	glossy, glassy, dull, fat
Optical properties
Ultraviolet fluorescence	no
Trait	White
Transparency	translucent to opaque
Other properties
Density	2.58 to 2.91 g / cm
Density	2,75
Distinctness
Magnetism	no
Radioactivity	no
Units of SI & STP unless otherwise stated.

Jasper is a sedimentary rock containing 80 to 95% of silica , often ranked with microcrystalline quartz, but may also contain the clay. It consists of radiolarian chalcedonic caught in a cement chalcedony. Fracture is flaky sometimes conchoidal. Jasper may have several aspects: Spotted, banded, red (or Oriental), spotted red on green, black (Sicily), etc.. It does not cons by quartz grains detritus. Sedimentary or volcanic in origin, so it's a mineral processing but is sometimes classified as rock mineral sometimes the views or dockage. Its main feature is its abundance in addition to its wide range of natural colors, can be estimated a priori that no color is impossible for the jasper that makes otherwise complex identification.

Varieties

Name	Etymology	Color	Composition	Metallogeny	Image
Basanite also called lydites	Fossilized wood by silica	Motley	This is a categorization of fossil wood shed in Jasper because the cells have been replaced by silica	Sedimentation zones of silica-rich deep
Cacholong	...	White	With the opal	..
Chrysoprase	...	Green to bluish green leek	...	..
Carnelian	...	Red to orange	Contains hematite quantity	..
Jasper brchoise	Just rock composition in the face	Beige to brown	We leave here to return to the minerals in rocks	..
Jasper earth	...	Beige to brown	...	..
Leopard jasper	Named as having spots like a leopard skin	Spotted	Dotted spots with centers sometimes pure quartz	..
Ocean jasper	...	Greenish patterned	...	..
Jasper plasma	...	Solid dark green	Colored by chlorite or serpentine	..
Bloodstone	...	Green background with red spots or completely red-brown	...	..
Orbicular jasper	...	Green background with gold spots	Its name Vikenti many formations in a circle	Scattered networks of tight spots concentric circular
Jasper zoned	Because with bedding traces of deposit	Multicolor	It contained the record of the different layers of deposits	Mixed with volcanic rocks
Lamparci or Dalmatian	...	White black spots	...	..
Lydian	...	Gray or black	presence of carbonaceous materials, some pyrite and a few grains phosphate	They often alternate with limestones and shales , with regular benches in the series of the Carboniferous.	...
Onyx	...	Black Brown	May be an agate or jasper, as its compposition	..
Phtanites	Comes from the Greek and means "I am ahead."	Gray or black	More clay than the Lydian, formed very small quartz crystals, some radiolarian still visible, or graphitic carbonaceous matter (hence their color), they are generally considered to be derived from marine deposits.	The phtanites often announce the transition to shale.
Sard	...	Brown	...	..
Sardonyx	...	Barriol	...	..
Unakite	...	orange green trench	...	..

Etymology

From the Latin from the Greek iaspidem (IASP), (himself from the Semitic languages (cf. yushphah Hebrew, Akkadian yashupu), probably of Persian Yasp .

Uses

The phtanites has been used to shape the prehistoric tools in Britain .

Jasper was also used for cutting tools: the case of Jasper Fontmaure example, but also very locally, jasper of Britain.

The Christians of the Middle Ages , made use of bloodstone to burn scenes of crucifixion , which led to the designation of "stone of the martyrs."

A superb specimen bloodstone with the seal of the Holy Roman Emperor Rudolf II is on display at the Louvre in Paris.

Jasper is often used to make cuts and also articles for the decoration of facades. St. Wenceslas Chapel in Prague , is an outstanding example. Some polished jasper develop surprising images to such an extent that some origins such as those of Oregon have received distinct names such Bruneau Owyhee jasper or .

Field

Jasper is extremely widespread but each piece is almost unique.

Training

It is either by hydrothermal or volcanic source via the sludge sediment deposition of radiolarian radiolarian and then sometimes called.

Criteria for the Discernment

Jasper consists of SiO ₂ so formed chalcedony , very close to the heliotrope , but most importantly, agates. They are different from others because of its infinite colors, its non-fluorescence, it does not contain detrital quartz, but more importantly because the jasper contains 5 to 20% of anything other than the original deposit. Identification is more difficult there is no fixing of objective criteria between these three formations, which all have the same origin. Many minerals will therefore remain disputed or indeterminate, the literature is sometimes contradictory on the subject. If we are dealing with very rich jaspers impurities, the density may be the determining factor as far as the average density of the added materials is very different from that of quartz. The formations are mostly spotted or banded agate and is the opacity that is often so crucial in the identification.

Gallery

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  Jasper Madagascar

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  Jasper twins

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  Red jasper

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  Beige and brown

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  Unakite

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  Mixed with the Chalcedony

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  Jasper Bhlchen

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  Macrofoto

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  Polished sphere

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  Dalmatian jasper

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  Phtanites block, the "rock St. Veronica" (Vendee)

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  Australian mookie

References

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