Phosphates: Variscite, Strengit
Diagnostic card.
On the photo is a sample of variscite. Below: spheroidal aggregates of strengite.
Fe PO 4 * 2 H 2 O - Variscite
Al PO 4 * 2 H 2 O - Strengite
Diamond orthogonality
Hardness 4-5
Specific weight 2.52
Cleavage is perfect
Fracture brittle, brittle
Green colour
Color in powder white
Glitter glass, waxy (data for variscite)
These two names are used for the initial and final terms of an isomorphic series that crystallize in a rhombic system. Variscite forms octahedral crystals. But more common are massive congestions, veins or nodules. Their color varies from pale yellow to emerald green. Shades of its color, which varies from apple-green to yellow and blue, this translucent mineral is due to impurities of iron and chlorine compounds.
Variscite is a mineral, water phosphate of aluminum, found in the form of pseudo-octahedral crystals and fine-grained kidney aggregates. At the AE Fersman Mineralogical Museum of the Russian Academy of Sciences, a polished slice of a stone from the United States of America is stored. With its color it resembles a green-azure surface of warm tropical waters. This is a sample of aqueous aluminum phosphate - variscite, named so for one of the districts of Saxony - Variscia. The discovery of variscite took place in 1837. In 1894, samples of green variscite fused with quartz were found in Utah (USA).
Strengite is represented by crystals of variable form (pseudo-octahedra, tablets, prisms) or forms aggregates of spheroidal outlines with a fibrous-radiant inner structure, painted in carmine-red and violet. The monoclinic analogue of the strangite is the clinostrendite forming tabular crystals of peach red or purple; It also occurs in the form of small massive clusters or inclusions of an earthy structure, painted in a pink-red color.
Diagnostic signs.
Soluble in acids with heating. Refractory.
Origin.
Strenghit is found in cracks and cavities of sedimentary rocks (especially including iron minerals). It can also form with secondary changes in other phosphates in the roof of ore deposits. Variscite is present in veins and fissures among quartzite schists and quartzites.
Deposits and applications.
About the strand was reported from the Grube-Eleonor mine in Thuringia, from the pegmatites of the Nagendorf deposit in Bavaria, from Mangualde in Portugal, from the district of Rockbridge in Virginia, Palermo to the state of New Hampshire. Klinoostrengit is known from Bavaria, New Hampshire and from Colombia. In Italy, he is described in the mine San Giovanne in Sardinia, in association with the purple anglesite. Variscite is noted in various places (Saxony, Austria and Bohemia). The most widely known deposit is Fairfield in Utah (USA). At present, the American variscite deposits are fully developed. The current source of variscite is the territory of Australia. Variscites have also been found in Germany and Brazil.
Sanded and polished variscite is used as an ornamental stone resembling turquoise. In the jewelry business, variscite was used as an ornamental stone as a substitute for turquoise in the form of cabochons. Variscite is usually used for the manufacture of various pendants and pendants. Do from pieces of variscite and beads, but the ring with variscite is rare. Below in the photo is a green variscite.
Sometimes, it is considered an independent mineral (and not a synonym for variscite). Deposits are known in the USA (Utah and Nevada) and Australia (Queensland). Confuse this mineral with chrysocolla, chrysoprase, turquoise. Sprouted variscite quartz or chalcedony from pcs. Utah (USA) is called an amrimax or variscite quartz.
Variscite. Montgomery County, Arkansas, United States. Photo: © А.А. Evseev.
Variscite (green). Australia. (2011).
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