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Phosphosiderite with Strengite


Phosphosiderite and strengite are both hydrous iron phosphates with the same composition; they are polymorphs. These specimens from Kreuzberg are unusual in that the two polymorphs phosphosiderite and strengite have grown together. Mineral specimens showing co-existing polymorphs are very unusual and indicate very specific formation conditions (i.e. P, T, chemistry). Bruhns & Buss (1890) named phosphosiderite for its composition, combining phosphorus with sideros, Greek for iron. Nies (1877) named strengite after Professor Johan A. Streng (1830-1897), mineralogist at the University of Giessen (Germany).

This consists of quartz and altered phosphate matrix. Purple strengite crystals to 3 mm and rose red phosphosiderite crystals to 2 mm line the cavities in the piece.

Price: $125

Item code: MS1401

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