Phoenicochroite
Appearance
Phoenicochroite | |
---|---|
General | |
Category | Sulfate (chromate) mineral |
Formula (repeating unit) | Pb2O(CrO4) |
IMA symbol | Phc[1] |
Strunz classification | 7.FB.05 |
Dana classification | 35.1.2.1 Anhydrous chromates |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/m |
Unit cell | a = 14 Å, b = 5.67 Å, c = 7.13 Å; β = 115.22°; Z = 4 |
Identification | |
Color | Dark red, bright red |
Crystal habit | Tabular crystals; thin coatings, and massive |
Cleavage | Perfect on {201} |
Tenacity | Sectile |
Mohs scale hardness | 2 1⁄2 |
Luster | Adamantine, resinous |
Streak | Brick-red |
Diaphaneity | Translucent |
Specific gravity | 5.75,[2] 7.01[3] |
Optical properties | Biaxial ( ) |
Refractive index | nα = 2.380, nβ = 2.440, nγ = 2.650 |
Birefringence | 0.270 (δ) |
2V angle | 58° (measured) |
Other characteristics | Health risks: contains carcinogenic and mutagenic chromate ion |
References | [4][2][3][5] |
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.[2] It is named from the Greek word φοίυικος for "deep red" and χρόα for "color", in allusion to its color.[2]
References
[edit]- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b c d Mindat.org Phoenicochroite on Mindat
- ^ a b Phoenicochroite in the Handbook of Mineralogy
- ^ Mineralienatlas
- ^ Phoenicochroite data on Webmin
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