Hydrated phosphate containing hydroxyl, jahnsite group
Specific gravity: 2.87 calculatedZnFe3+ 2 (PO4 )2 (OH)2 ·6.5H2O
Colour: Yellow, brown
Jahnsite-(CaMnZn) is a relatively new mineral, approved in 2019 and to date (July 2022) reported only from the
At the type locality, the 67 m level, Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany, jahnsite-(CaMnZn) forms as thin yellow crusts and brown epitactic growths on altered phosphophyllite, both of which comprise lath-like crystals up to 100 μm long. The crystals contain intergrowths of jahnsite-(CaMnZn) and jahnsite-(CaMnMn) on a scale of ~50 μm (MM 84.547-553).
The jahnsite-(CaMnZn) was found in an oxidized nodule of former triphylite, now replaced by phosphophyllite. It is a low temperature, secondary mineral formed by alteration of primary phosphates in a zoned granitic pegmatite. Associated minerals include chalcophanite, hopeite, jahnsite-(CaMnMn), zinc-bearing laueite, scholzite-parascholzite, parahopeite, schmidite, stewartite, vivianite, whitmoreite-earlshannonite, zincostrunzite and apatite (HOM).
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