pitchblende


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to pitchblende: radium

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.

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

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.

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
References in periodicals archive ?
Estimation of uranium (VI) ([micro]g/mL) in pitchblende ore sample Sample Amount of U (VI) PPM Taken Found * Error (%) Pitchblende 20 19.
The ore stage was marked by the formation of coffinite and pitchblende, together with small amount of authigenic chlorite, hydrated titanium oxide (leucoxene?
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.
Somair has three open-pit operations near Arlit that recover uranium silicate and minor pitchblende.
Collecting crystals is a popular Swiss hobby, and many displays include minerals -- such as zircon, coffinite, carnotite, monazite, brannerite, titanite and pitchblende -- containing radon-emitting uranium or thorium.
Trenching has exposed uranium mineralization occurring as veins and pockets of pitchblende.
Pitchblende is the principal source of which two radioactive elements?
46 holes drilled this winter with 37 successfully encountering anomalous radioactivity with associated massive and disseminated pitchblende mineralization (overall 80% success ratio of intersecting mineralization);
8 m wide, 360 m large and 160 m deep), and consists of pitchblende with iron sulphides that contain variable amounts of arsenic, oxides and carbonates.
In the preface to Einstein's Monsters, he preaches against nuclear holocaust and wants the big, bad bombs returned to pitchblende.
The most common uranium mineral is pitchblende, with lesser concentrations of coffinite and brannerite.