Drysdallite
(repeating unit)MoSe1.5S0.5 IMA symbol Dry[1] Strunz classification 2/D.25-30 Dana classification 1.12.10.2 Crystal system Hexagonal - Dihexagonal Dipyramidal Space group P63/mmc (No. 194) Unit cell 120.94 ų (Calculated from Unit Cell) Identification Formula mass 230.41 gm Colour Grayish-black Cleavage Perfect Tenacity Waxy, pliable, difficult to pulverise Mohs scale hardness 2 Luster Metallic Streak Brown-black Specific gravity 6.248 (Calculated) Density 6.248 g/cm3 (Calculated) Pleochroism Strong, white to very pale grey, to pinkish grey
Drysdallite is a rare molybdenum selenium sulfide mineral with formula Mo(Se,S)2. It crystallizes in the hexagonal system as small pyramidal crystals or in cleavable masses. It is an opaque metallic mineral with a Mohs hardness of 1 to 1.5 and a specific gravity of 6.25. Like molybdenite it is pliable with perfect cleavage.
It was first described in 1973 for an occurrence in an oxidized uranium deposit near Solwezi, Zambia. It was named for Alan Roy Drysdall, the director of the Zambian geological survey.
References
- ^ 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.
- Handbook of Mineralogy
- Webmineral
- Mindat
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