Viewable from two sides, this specimen of silver and acanthite has been partially etched out of enclosing, massive, white calcite. The brilliant luster of the spinel twinned silver, in crystals to .8 cm across is offset by the matte black acanthite crystals, to 2 mm across. The color contrast between the calcite and the silver/acanthite is attractive. This is a rich, hefty specimen!