Achávalite
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Achávalite is a selenide mineral that is a member of the nickeline group. It has only been found in a single Argentinian mine system, being first discovered in 1939 in a selenide deposit. The type loc
Black metallic crystals of achávalite from Cacheuta Mine, Mendoza, Argentina
Hermann–Mauguin notation
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In geometry, Hermann–Mauguin notation is used to represent the symmetry elements in point groups, plane groups and space groups. It is named after the German crystallographer Carl Hermann and the Fren
Achávalite
…Selenide mineral Formula (Fe,Cu)Se IMA symbol Ahv Strunz classification 2.CC.05 Crystal system Hexagonal Crystal class Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m) Space group P63/mmc Unit cell a = 3.636, c = 5.946 [Å], Z = 2 Identification Formula mass 134.81 g/mol Color Dark grey Mohs scale hardness…
Three point groups with their respective Hermann–Mauguin notation, stereographic projections, and symmetry elements.