Stolzite

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Stolzite
Stolzite-t07-25b.jpg
Stolzite, Broken Hill, Australia (size: 3.6 x 3.0 x 2.6 cm)
General
Category Tungstate minerals
Formula
(repeating unit)
PbWO4
Strunz classification 07.GA.05
Crystal symmetry Tetragonal 4/m - dipyramidal
Unit cell a = 5.461 Å, c = 12.049 Å; Z = 4
Identification
Color Reddish brown, brown, yellowish gray, smoky gray, straw-yellow, lemon-yellow; may be green, orange, red
Crystal habit Crystals dipyramidal to tabular
Crystal system Tetragonal
Cleavage Imperfect on {001}, indistinct on {011}
Fracture Conchoidal to uneven
Tenacity Brittle
Mohs scale hardness 2.5 - 3
Luster Resinous, subadamantine
Streak White
Diaphaneity Translucent to transparent
Specific gravity 8.34
Optical properties Uniaxial (-)
Refractive index nω = 2.270 nε = 2.180 - 2.190
Birefringence δ = 0.090
References [1][2][3]

Stolzite is a mineral, a lead tungstate; with the formula PbWO4. It is similar to, and often associated with, wulfenite which is the same chemical formula except that the tungsten is replaced by molybdenum. Stolzite crystallizes in the tetragonal crystal system and is dimorphous with the monoclinic form raspite.[2]

Lead tungstate crystals have the optical transparency of glass combined with much higher density (8.28 g/cm3 vs ~2.2 g/cm3 for fused silica). They are used as scintillators.

It was first described in 1845 for an occurrence in Krusne Hory (Erzgebirge), Czech Republic and named after Joseph Alexi Stolz of Teplice in Bohemia.[2][3] It occurs in oxidized hydrothermal tungsten-lead ore deposits typically in association with raspite, cerussite, anglesite, pyromorphite and mimetite.[1]

See also[edit]

References[edit]

Stolzite crystal from the Darwin District, Inyo County, California (size: 2.0 x 1.7 x 1.6 cm)