pitchblende


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pitchblende

(pĭch`blĕnd'), dark, lustrous, heavy mineral, a source of radium and uranium. Largely natural uranium oxides, triuranium octaoxide (U3O8) and uranium dioxide (UO2), it usually contains some lead and variable amounts of thorium and rare-earth elements. It is massive in form, frequently with a botryoidal, or grape-cluster, appearance, and has a variable but high specific gravity. Pitchblende is greenish, brownish, or black in color, with a pitchy to submetallic luster. The uranium yield is from 50% to 80%. Uraninite, a closely related ore richer in uranium (uranium dioxide), commonly crystallizes in the cubic system. It yields 65% to 80% uranium and has a specific gravity somewhat higher than that of pitchblende. The color range is from deep black to brown. Both ores occur as primary constituents of quartz veins and with other metals. They supply radium and polonium in addition to uranium. Although the ores occur in small quantities throughout the world, the Great Lakes region of Canada, Congo (Kinshasa), the Czech Republic, the Colorado Plateau, Australia, and South Africa are the major sources.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Pitchblende

 

(nasturan), a variety of uraninite occurring as massive and colloform aggregates that contain variable quantities of UO3 (predominant constituent) and UO2. Admixtures include radiogenic lead, calcium, sometimes rare-earth elements of the yttrium subgroup, and up to 2–3 percent H2O. Pitchblende’s crystal structure generally corresponds to that of uraninite; however, pitchblende is converted to an amorphous state when UO3 dominates. An opaque black mineral with a pitchlike luster, it has a hardness of 4—6 on Mohs’ scale. Its density, depending on the UO2: UO3 ratio, varies from 6,000 to 9,200 kg/m3. The mineral is highly radioactive.

Pitchblende is one of the most widely occurring uranium minerals. It is found in complex hydrothermal ore deposits in association with tin and tungsten minerals, as well as with arsenides and sulfarsenides of cobalt, nickel, and iron, and with sulfides of copper, lead, bismuth, silver, and other metals. In uranium-iron ore deposits it occurs in association with hematite, magnetite, and other minerals. It also occurs in sedimentary deposits and in conglomerates, where powdery, earthy aggregates of the mineral are also commonly formed. Pitchblende is one of the most commercially important minerals contained in uranium ores.

G. P. BARSANOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

pitchblende

[′pich‚blend]
(mineralogy)
A massive, brown to black, and fine-grained, amorphous, or microcrystalline variety of uraninite which has a pitchy to dull luster and contains small quantities of uranium. Also known as nasturan; pitch ore.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

pitchblende

a blackish mineral that is a type of uraninite and occurs in veins, frequently associated with silver: the principal source of uranium and radium. Formula: UO2
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Marie meanwhile took on the herculean task of isolating radium from pitchblende. Their workplace was inadequate in many ways: they were given the use of a cavernous hangar at the Ecole de Physique et Chimie--a wooden shed with a glass roof that didn't keep out the rain.
A synthetic mixture of Pitchblende ore was prepared by mixing in the same ratio, as the components would be present in Pitchblende ore.
The main uranium-ore stage characterized by the formation of coffinite and pitchblende was dated by the U/Pb method (Anderson et al., 1989).
In 1789 uranium oxide was extracted from pitchblende, a uranium-containing ore discovered in Bohemia.
From 1930 to 1960 the pitchblende deposits at the eastern tip of the Great Bear Lake, where the town of Port Radium was built from scratch, were exploited to obtain radium and other radioactive elements.
I'm not a stellar performer when it comes to killing pitchblende targets, but the new Orion Upland made hitting easy.
On February 17th, 1898, she tested a sample of heavy black pitchblende (a naturally-occurring mineral containing uranium) which she found was emitting unexpectedly strong radiation.
Armed with information from his friends in government and industry, David typed up a list of sources for fourteen radioactive isotopes..Americium-241, he learned from the Boy Scout atomic-energy booklet, could be found in smoke detectors; radium-226, in antique luminous dial clocks; uranium-238 and minute quantities of uranium-235, in a black ore called pitchblende; and thorium-232, in Coleman-style gas lanterns.
Imagine the shock, disbelief, and exhilaration in that order--that rocked the scientific community in the waning years of the 19th century when science had just concluded that transmutations were nothing more than wistful dreams: Wilhelm Roentgen discovered x rays in 1895, which Lord Kelvin--with an R&D attitude that was well ahead of its time--dismissed out of hand as a charlatan's trick; then this was followed by Henri Becquerel's discovery of x-ray-like activity in uranium two years later, with the subsequent discovery and separation of polonium and radium from pitchblende ore by Pierre and Marie Curie by 1898.
In 1789 Klaproth (see 1784), who was working with a heavy black ore called pitchblende, obtained a yellow compound that contained a hitherto unknown element.
The sites allegedly became contaminated when radium extraction and application industries, operating in the area from about 1913 to 1925, disposed of their wastes (spent carnotite or pitchblende ores, byproducts, etc.) on what was then vacant land.