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(mineralogy) A mineral composed of calcium tungstate, with the chemical formula CaWO₄; one of the principal ores for tungsten.

Scheelite

(mineralogy) A mineral composed of calcium tungstate, with the chemical formula CaWO₄; one of the principal ores for tungsten.

Tungstate mineral – CaWO₄ – Sch – 7.GA.05 – Tetragonal – Dipyramidal (4/m) – I4₁/a – A = 5.2429(3), Å – C = 11.3737(6) Å; Z = 4 – Colorless, white, gray, dark brown, brown, tan, pale yellow, yellow-orange, golden yellow, pale shades of orange, red, green, etc.; colorless in transmitted light and may be compositionally color zoned – Pseudo-octahedra, massive, columnar, granular – Common, penetration and contact twins, composition plane {110} or {001} – On {101}, distinct; on {112}, interrupted; on {001}, indistinct – Subconchoidal to uneven – Brittle – 4.5–5 – Vitreous to adamantine – White – Transparent to opaque – 5.9–6.1 – Uniaxial (+) – N_ω = 1.918–1.921, n_ε = 1.935–1.938 – Δ = 0.017 – Definite dichroic in yellow (yellow to orange-brown) – With difficulty – Soluble in alkalis. Insoluble in acids – Fluorescence under short-wave UV is bright blue, bluish white to yellow. Specimens with more molybdenum tend to fluoresce white to yellow, similar to powellite. Occasionally, it fluoresces red under mid-wave UV.

(mineralogy) A mineral composed of calcium tungstate, with the chemical formula CaWO₄; one of the principal ores for tungsten.

Structure of CaWO₄