Phoenicochroite
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Phoenicochroite | |
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Deep red Phoenicochroite cystal, with orange-yellow schwartzembergite. San Francisco Mine, Tocopilla Province, Chile. Photo width 1.5 mm. | |
General | |
Category | Chromate mineral |
Formula (repeating unit) | Pb2O(CrO4) |
Strunz classification | 07.FB.05 |
Crystal symmetry | monoclinic |
Unit cell |
a: 14 Å, b: 5.67 Å, c: 7.13 Å β: 115.22° |
Identification | |
Color | dark red, bright red |
Mohs scale hardness | 2½ |
Streak | brick-red |
Specific gravity | 5.75 g/cm3 |
Optical properties | biaxial (+) |
Refractive index | nα = 2.380, nβ = 2.440, nγ = 2.650 |
Birefringence | 0.270 (δ) |
2V angle | 58° (measured) |
Phoenicochroite, also known as melanochroite, is a lead chromate mineral with formula Pb2OCrO4. It forms striking orange red crystals. It was first discovered in 1839 in Beryozovskoye deposit, Urals, Russia.[1]
References
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