- 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 Geiger-Mueller counter encased in a watertight container, which can be lowered into a borehole and used to log the intensity of the gamma rays emitted by the radioactive substances in the rock formations traversed.
Industry:Mining
A gem material consisting of small fragments of genuine amber artificially united or reconstructed by heat and pressure; may be characterized by an obvious flow structure or a dull spot left by a drop of ether. Also spelled ambroid.
Industry:Mining
A gem material consisting of small fragments of genuine amber artificially united or reconstructed by heat and pressure; may be characterized by an obvious flow structure or a dull spot left by a drop of ether. Also spelled ambroid.
Industry:Mining
A gem variety of opal that exhibits a brilliant play of delicate colors by diffraction of light from close-packed 150- to 300-mm spheres of cristobalite-tridymite. The color of the bulk material may be black or white. Compare: common opal.
Industry:Mining
A gem with a row or rows of steplike facets around the table and culet (or small lower terminus of the gem, parallel to the table), or around the culet alone.
Industry:Mining
A gem-quality variety of olivine (forsterite) in Hawaii; forms phenocrysts in basalt; also in derived sands.
Industry:Mining
A gemstone that has been heated, stained, oiled, or coated; treated by various types of irradiation, in order to improve or otherwise alter its color; or laser-drilled to make flaws inconspicuous. Also, a stone that has been preserved from dehydration, such as an opal whose cracks have been filled with oil or other liquid; or one in which special effects have been produced; e.g., amber with "spangles" (tension cracks).
Industry:Mining
A gemstone with color altered by a coloring agent, such as a dye, or by impregnation with a substance, such as sugar, followed by chemical or heat treatment, which usually produces a permanent color; e.g., green chalcedony. Compare: burnt stone.
Industry:Mining
