Wulfenite, (on Dolomite)

Mineral: Wulfenite, Dolomite
Chemistry: PbMoO4
Size: 78 mm
Owner: Carl Acosta
Photographer: John Schneider

This is an example of a dolomite “cast”, in which a layer of dolomite crystallised over a pre-existing mineral, possibly calcite, which has subsequently dissolved away to leave a shell-like structure of dolomite with a texture that mimics the surface over which it originally formed.  In this case the dolomite is coloured pink, probably due to the presence of cobalt (although this has not been analysed).

What makes this specimen particularly interesting, however, is the presence of several well-formed, buff-coloured wulfenite crystals of typical, thick tabular habit, the largest of which measures 19 mm across.