Dolomite, (after Calcite, w. Malachite)

Size: 110 mm
Owner: Jim Robison
Photographer: John Schneider

The two photographs show the front (convex) and back (concave) surfaces of a dolomite cast, believed to be epimorphous after calcite (?), the original generation of which has been removed by solution processes. Radial sprays of malachite, (mostly < 1 mm), and second generation calcite rhombs (to 3 mm) have grown on the convex face of the cast, where they are somewhat sparsely distributed (Photo 1).  These same two minerals have also crystallised on the concave surface, but in much greater profusion, with larger crystals (or aggregates) and far more densely populated (Photo 2).