Quartz (Var: Chalcedony), Limonite
Stöckaten, Siebenhitz, Köditz, Hof District, Upper Franconia, Bavaria, Germany
A rare specimen, the only one I've found in this mine. The cubic crystals are perimorphs, I think, before the transformation it was fluorite, possible in this location. Inside the damaged cube a rest of weathered fluorite is visible.
The size of the intact, hollow cube is 27 x 17 mm.
© klaus ludwig