- 行业: 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 granite characterized by phenocrysts of potassium feldspar and quartz that enclose clusters of radially arranged acicular tourmaline crystals in a groundmass of quartz, tourmaline, alkali feldspar, brown mica, and cassiterite. Its name is derived from Luxulyan, Cornwall. Also spelled: luxulianite; luxulyanite. Var: luxuliane.
Industry:Mining
A granite containing both dark mica (biotite) and light mica (muscovite). This rock was called true granite by Rosenbusch and binary granite by Keyes. Compare: aplogranite.
Industry:Mining
A granite having miarolitic cavities; a textural modification of normal granite.
Industry:Mining
A granitic rock, occurring in the Alps, that has gneissic structure, contains sericite, chlorite, epidote, and garnet, and shows evidence of a composite origin or of crystallization (or partial recrystallization) under stress after consolidation. Also spelled protogene. The term, dating from 1806, is obsolete.
Industry:Mining
A grant by Act of Congress, to convey water over or across the public domain, for mining purposes.
Industry:Mining
A granular plutonic rock containing approx. equal amounts of orthoclase and plagioclase, and thus intermediate between syenite and diorite. Quartz is minor or absent. Either hornblende or diopside, or both, are present and biotite is a common constituent. Accessories are apatite, zircon, sphene, and opaque oxides. The intrusive equivalent of latite.
Industry:Mining
A group of plutonic rocks intermediate in composition between syenite and diorite, containing both alkali feldspar (usually orthoclase) and plagioclase feldspar, commonly more of the former; also, any rock in that group. Generally considered a syn. of monzonite, but may also include both monzonite and rocks intermediate between monzonite and diorite (Streckeisen, 1967).
Industry:Mining
