Pyromorphite on Barite Chaillec Mine Chaillac Inbra Central France

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Dimensions (mm) 75 x 62 x 41mm
Weight (carats) 762 carats
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Pyromorphite on Barite

Pyromorphite on Barite Chaillec Mine Chaillac Inbra Central France list price $650.00

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb5(PO4)3Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. It is part of a series with two other minerals: mimetite (Pb5(AsO4)3Cl) and vanadinite (Pb5(VO4)3Cl), the resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests. Paecilomyces javanicus is a mold collected from a lead-polluted soil that is able to form biominerals of pyromorphite [4]

They were formerly confused under the names green lead ore and brown lead ore (German: Grünbleierz and Braunbleierz). The phosphate was first distinguished chemically by M. H. Klaproth in 1784,[5][6] and it was named pyromorphite by J. F. L. Hausmann in 1813.[7][8] The name is derived from the Greek for pyr (fire) and morfe (form) due to its crystallization behavior after being melted.[2]

The color of the mineral is usually some bright shade of green, yellow or brown, and the luster is resinous. The hardness is 3.5 to 4, and the specific gravity 6.5 - 7.1. Owing to isomorphous replacement of the phosphorus by arsenic there may be a gradual passage from pyromorphite to mimetite. Varieties containing calcium isomorphously replacing lead are lower in density (specific gravity 5.9 - 6.5) and usually lighter in color; they bear the names polysphaerite (because of the globular form), miesite from Mies in Bohemia, nussierite from Nuizière, Chénelette, near Beaujeu, Rhône, France, and cherokine from Cherokee County in Georgia.

aryte or barite (BaSO4) is a mineral consisting of barium sulfate.[2] The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte is generally white or colorless, and is the main source of barium. Baryte and celestine form a solid solution (Ba,Sr)SO4.[1]

The unit cell of baryte

The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among alchemists for the phosphorescent specimens found in the 17th century near Bologna by Vincenzo Casciarolo.[6]

The American Petroleum Institute specification API 13/ISO 13500, which governs baryte for drilling purposes, does not refer to any specific mineral, but rather a material that meets that specification. In practice, however, this is usually the mineral baryte.

The term “primary barytes” refers to the first marketable product, which includes crude baryte (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation. Most crude baryte requires some upgrading to minimum purity or density. Baryte that is used as an aggregate in a “heavy” cement is crushed and screened to a uniform size. Most baryte is ground to a small, uniform size before it is used as a filler or extender, an addition to industrial products, in the production of barium chemicals or a weighting agent in petroleum well drilling mud.

Name

The name baryte is derived from the Ancient Greek: βαρύς, translit. barús, ‘heavy’. The American spelling is barite.[2][7] The International Mineralogical Association initially adopted “barite” as the official spelling, but recommended adopting the older “baryte” spelling later. This move was controversial and was notably ignored by American mineralogists.[8]

Other names have been used for baryte, including barytine,[9] barytite,[9] barytes,[10] heavy spar,[2] tiff,[3] and blanc fixe.[11]

Mineral associations and locations[edit]

Baryte with galena and hematite from Poland

Baryte and dolomite from Frizington, West Cumberland Iron Field, North and Western Region (Cumberland), Cumbria, England

Abandoned baryte mine shaft near Aberfeldy, Perthshire, Scotland

Baryte occurs in a large number of depositional environments, and is deposited through a large number of processes including biogenic, hydrothermal, and evaporation, among others.[1] Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore. It is often associated with the minerals anglesite and celestine. It has also been identified in meteorites.[12]

Baryte has been found at locations in Brazil, Nigeria, Canada, Chile, China, India, Pakistan, Germany, Greece, Guatemala, Iran, Ireland (where it was mined on Benbulben[13]), Liberia, Mexico, Morocco, Peru, Romania (Baia Sprie), Turkey, South Africa (Barberton Mountain Land),[14] Thailand, UK (Cornwall, Cumbria, Dartmoor/Devon, Derbyshire, Durham,[15] Perthshire, Argyllshire and Surrey[2]) and in the US from Cheshire, Connecticut, De Kalb, New York and Fort Wallace, New Mexico. It is mined in Arkansas, Connecticut, Virginia, North Carolina, Georgia, Tennessee, Kentucky, Nevada and Missouri.[2]

World baryte production for 2016 was 7.3 million tonnes. The major barytes producers (in thousand tonnes, data for 2016) are as follows: China (3,100), India (1,300), Morocco (550), United States (430), Turkey (240), Russia (210), Mexico (200), Iran (200), Kazakhstan (190) and Thailand (160).[16]

The main users of barytes in 2016 were (in million tonnes) Middle East (1.74), US (1.60), China (1.50), the European Union and Norway (0.65), Russia and CIS (0.45), South America (0.28), India (0.25), and Africa (0.17).[16]

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Auction ID 736009
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Starts 27th Feb 2018 3:22pm PST

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