Dessauite-(Y)
Dessauite-(Y) is a mineral member of the crichtonite group with the formula (Sr,Pb)(Y,U)(Ti,Fe3+)20O38. It is associated with derbylite, hematite, rutile, karelianite, siderite, and calcite. Founded in the Buca della Vena Mine, Tuscany, Italy, the mineral was called dessauite in honor of professor Gabor Dessau (1907–1983).
Intro adapted from Wikipedia (CC BY-SA).
Dessauite-(Y) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Sr(Y,U,Mn)Fe₂(Ti,Fe,Cr,V)₁₈(O,OH)₃₈.
It crystallizes in the hexagonal crystal system (space group R-3). It is a member of the Crichtonite structural group.
Key properties: Mohs hardness 2.5; specific gravity 5.42; Pale blue streak; Adamantine, pearly on cleavages luster; optically uniaxial.
IMA symbol Dss-Y, IMA status: approved, named in 1994.
Found in oxidized manganese ores (Mendip Hills, England); a secondary mineral in deeply oxidized Pb–Cu ores (Tiger, Arizona, USA); in slag exposed to seawater.
It is found associated with Chloroxiphite, hydrocerussite, mendipite, cerussite (Mendip Hills, England); boleite, wherryite, hydrocerussite, leadhillite, phosgenite, caledonite.
Its name comes from the Greek for separate from, and the related mineral boleite.