Proustite


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proustite

[′prü‚sīt]
(mineralogy)
Ag3 AsS3 A cochineal-red mineral that crystallizes in the rhombohedral system, consists of silver arsenic sulfide, is isomorphous with pyrargyrite, and occurs massively and in crystals. Also known as light-red silver ore; light-ruby silver.

Proustite

 

(also light red silver ore), a mineral of chemical composition Ag3AsS3. It crystallizes in the trigonal system, and its basic structure consists of pyramidal groups of AsS3 and spiral-shaped chains of Ag2S. Proustite occurs as disseminated grains, crystals, and compact masses. It is ruby red in color and brittle, with a hardness of 2–2.5 on Mohs’ scale and a density of 5,570–5,670 kg/m3. It is formed chiefly in lead-zinc-silver hydrothermal ore deposits. Although it is one of the basic minerals in silver ore, it is less widespread than pyrargyrite and does not form significant accumulations.

In the USSR, there are deposits of proustite in the Altai, the Far East, Kazakhstan, and Middle Asia. The mineral is also found in the German Democratic Republic, the Federal Republic of Germany, Czechoslovakia, Canada, Mexico, Bolivia, Peru, and Chile. Methods have been developed for growing proustite crystals of optical quality from melts. Proustite is a ferroelectric and is transparent in the infrared region. It is considered a promising material for nonlinear optics and acousto-optical devices.

A. S. MARFUNIN

References in periodicals archive ?
The principal minerals which are found either banded or disseminated within the 90% quartz matrix include pyargyrite, ancanthite, proustite, polybasite, miargiarite, galena, sphalerite, pyrite, and arsenopyrite.
The fluorites, pink quartzes, even the delicate greens of some spodumene, the faintly blushing calcites and the rhodochrosites, also sensibly succumb to these exposures, while it is a matter of common annoyance to find that the realgars, cerargyrites, proustites, cuprites, crocoite, and sulphurs go through changes that slowly alter their substance, texture and appearance.
20, D-53227 Bonn, Germany), there is hope, after all, for major improvement in the proustite specimens which have been trickling for several years now from the famous Imiter silver mine near Ouarzazate, Morocco.
The locality is the Uchucchacua mine, Oyon Province, Lima Department, already famous for its acanthite, silver, proustite and "arsenpolybasite" specimens.
1506 Proustite, O'Brien mine, Cobalt, Ontario, Canada, no.
At Tamdrost proustite occurs in calcite veins as dark red crystals not exceeding 4 mm, with lollingite and native silver.
They're all here, in multiple samples ranging in quality from "study grade" to absolutely superb: Freiberg acanthite and stephanite, Schneeberg proustite and erythrite and roselite and uranium-bearing species, Andreasberg pyrargyrite and dyscrasite and fluorite and pink apophyllite, Siegerland malachite and anglesite and millerite and galena, Schwarzwald fluorite and barite and silver, Obermoschel cinnabar and moschellandsbergite, Ems pyromorphite and cerussite, Johanngeorgenstadt mimetite, Ohrenstock hausmannite, Fichtelgebirge topaz and microcline and herderite, Ehrenfriedersdorf cassiterite and fluorapatite, Ilfeld manganite, Ronneburg whewellite, Hagendorf phosphates .
5 ("Mexico II"); the 7-cm cluster of proustite crystals from Chanarcillo, Chile; the finest extant specimen of spangolite from Bisbee, Arizona; and others almost as well known.
Many cases at the Main Show tackled South American Minerals, the hands-down best of them being the Smithsonian's case, with 21 amazing pieces including a totally gemmy blue 5-cm euclase crystal from Ouro Preto, Minas Gerais, Brazil; a single, thick, lustrous, still-red proustite crystal 9.
Any of the rarer species from Silvermines such as jordanite, proustite, tennantite etc.
He also got apophyllite and valencianite from Guanajuato, and had spent a week in Zacatecas (10) buying specimens of proustite, pyrargyrite, stephanite and native silver.
his case of superlative thumbnails, and one of these thumbnails, his resplendent, transparent, emphatically red proustite from Chanarcillo, Chile, took the Lidstrom award for the show's single best specimen in competition.