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The origin conditions of primary and detrital scheelite related to the Variscan granites in the Central Sudetes (SW Poland)
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
Primary scheelite mineralisation connected with the Variscan acid magmatism was recognised in several parts of the Kłodzko-Złoty Stok massif and its eastern metamorphic cover (Fig. 1). The skarn-like mineralisation at the Zloty Stok As-Au deposit bears scheelite most commonly as impregnations, grain clusters to 3 cm in size (1st generation) and veinlets (2nd generation). The 1st scheelite generation consists of the sub- and euhedral grains of the size of few hundredths to few mm formed during oxide substage (with magnetite, titanite and powellite) that followed calc-silicate substage (quartz, calcite, diopside, garnet) and preceded the gold-bearing arsenide-sulphide substage. The 1st generation scheelite developed from metasomatic fluids of the concentration of 5 wt % NaCl equiv. at about 500°C mobilised by the Kłodzko-Złoty Stok granodiorite intrusion, which altered the primary calcareous rocks into calc-silicate skarn type rocks. The 2nd generation scheelite appeared as encrustations with quartz and calcite in central parts of veinlets and as irregular fillings of voids in calc-silicate rocks.
Properties of the Elements and Inorganic Compounds
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Name Polymidite Portlandite Powellite Protoenstatite Proustite Pseudowollastonite Pyrargyrite Pyrite Pyrolusite Pyrope Pyrophyllite Pyroxmangite Pyrrhotite Quartz () Quartz () Rammelsbergite Realgar Retgersite Riebeckite Rutile Safflorite Fe-Sanidine Sanmartinite Sapphirine Schorl Selenium (gray) Sellaite Senarmontite Shandite Shortite Siderite Silicon Sillimanite Silver Silver telluride I Silver telluride II Fe-Skutterudite Ni-Skutterudite Smithsonite Sodium melilite Sperrylite Spessartite Sphalerite Sphene Spinel Spodumene Spodumene () Staurolite Sternbergite Stibnite Stilleite Stishovite Stolzite Stromeyerite Sulfur (monoclinic) Sulfur (rhombohedral) Formula Crystal system cubic hexagonal tetragonal orthorhombic rhombohedral triclinic rhombohedral cubic tetragonal cubic monoclinic triclinic hexagonal hexagonal hexagonal orthorhombic monoclinic tetragonal monoclinic tetragonal orthorhombic monoclinic monoclinic monoclinic rhombohedral hexagonal tetragonal cubic rhombohedral orthorhombic rhombohedral cubic orthorhombic cubic cubic cubic cubic cubic rhombohedral tetragonal cubic cubic cubic monoclinic cubic monoclinic tetragonal monoclinic orthorhombic orthorhombic cubic tetragonal tetragonal orthorhombic monoclinic rhombohedral Structure type spinel cadmium iodide scheelite Z a/Å 9.480 3.5933 5.226 9.25 10.816 6.90 11.052 5.4175 4.388 11.459 5.14 7.56 3.440 4.9136 4.999 4.757 9.29 6.782 9.729 4.5937 5.231 8.689 4.691 9.96 16.032 4.3642 4.621 11.152 5.576 4.961 4.6887 5.4305 7.4843 4.0862 5.29 6.585 8.1814 8.3300 4.6528 8.511 5.968 11.621 5.4093 7.07 8.080 9.451 7.5332 7.90 11.60 11.229 5.6685 4.1790 5.4616 4.066 11.04 10.818
Eu3+-Based Orange-Red-Emitting Inorganic Color Convertors: An Overview
Published in Sanjay J. Dhoble, B. Deva Prasad Raju, Vijay Singh, Phosphors Synthesis and Applications, 2018
The Eu3+-activated Ca4LnNbMo4O20(Ln = Gd, La) phosphor with a powellite-type structure was synthesized and its PL properties investigated in detail [98,99]. This structure is considered to be a combination between two individual hosts, 4(CaMoO4) + GdNbO4, which bear a different crystal structure (CaMoO4 has a powellite- type structure and GdNbO4 has a fergusonite structure) [100].
Co-extraction of tungsten and molybdenum from refractory scheelite–powellite blend concentrates by roasting with Na2CO3 and SiO2 and leaching with water
Published in Canadian Metallurgical Quarterly, 2018
Weizheng Yang, Wu Wang, Xiaochao Wu, Kaijun Yang, Qingkui Li, Jilin He
The X-ray diffraction (XRD) pattern of the raw material, presented in Figure 1(a), shows that the main metallic minerals in scheelite–powellite ore are scheelite, powellite, molybdenite, and magnetite, whereas the main gangue minerals are quartz, dolomite, and fluorite constituents. The XRD patterns of the pre-treated scheelite–powellite ore presented in Figure 1(b) show that the main mineral phases identified are scheelite, powellite, and fluorite.