- المجال: Mining
- Number of terms: 33118
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The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A rare type of twinning in quartz in which there appears to be a 180 degrees rotation around c with reflection over (1120) or over (0001). The crystal axes are parallel, but the polarity of the a axis is not reversed in the twinned parts.
Industry:Mining
A rare variety of tourmaline, olive green in daylight, changing to brownish-red in most artificial light.
Industry:Mining
A rare variety of tourmaline, olive green in daylight, changing to brownish-red in most artificial light.
Industry:Mining
A rare, silvery-white metal. Symbol, Re. Occurs in very small quantities in platinum ores and in columbite, gadolinite, and molybdenite. Used for filaments for mass spectrographs and ion gages; for thermocouples and photoflash lamps.
Industry:Mining
A rare, weakly radioactive, orthorhombic or monoclinic mineral, Ca(Ce,Nd,Y,La)(CO<sub>3</sub>)<sub>2</sub>F , usually found in pegmatites associated with aegirite, microcline, astrophyllite, fluorite, gadolinite, xenotime, cordylite, and catapleiite. May be related to parisite. Also spelled synchysite.
Industry:Mining
A rare-earth element that has a bright silvery luster, is soft, malleable and quite ductile. Symbol, Yb. Occurs with other rare-earths in a number of rare minerals. Commercially recovered from monazite sand. Has a possible use in improving the mechanical properties of stainless steel; few other uses have been found.
Industry:Mining
A rare-earth element that has a silvery-metallic luster. Symbol, Y. Occurs in nearly all of the rare-earth minerals. Recovered commercially from monazite sand and from bastnasite. Widely used: in color television tubes; to reduce the grain size in chromium, molybdenum, zirconium, and titanium; to increase the strength of aluminum and 3642 magnesium alloys; as a deoxidizer for vanadium and other nonferrous metals; in nuclear technology for its high neutron transparency.
Industry:Mining
A rare-earth oxide; white; Dy<sub>2</sub>O<sub>3</sub>; isometric; sp gr, 7.81 (at 27 degrees C); and melting point, 2,340+ or -10 degrees C. Used as a nuclear-reactor control-rod component and a neutron-density indicator.
Industry:Mining
A rare-earth oxide; white; Dy<sub>2</sub>O<sub>3</sub>; isometric; sp gr, 7.81 (at 27 degrees C); and melting point, 2,340+ or -10 degrees C. Used as a nuclear-reactor control-rod component and a neutron-density indicator.
Industry:Mining
