Quartz epimorph of Calcite

specimen number:
2123010

location:
Artigas, Uruguay

description:
Attractive purple glassy and mostly gemmy crystals of quartz averaging 0.8 cm in size forming an epimorph after a now gone scalenohedral calcite crystal. Classic material for this locality, this is in terrific condition all around. This is the variety of quartz known as amethyst.

An epimorph forms when one mineral grows as a shell around another mineral crystal and the original mineral later dissolves away, leaving a hollow cast of the earlier crystal. In the case of quartz after calcite, quartz crystals grow over a calcite crystal and completely enclose it. When the calcite later dissolves, a hollow quartz shell remains that preserves the external shape of the original calcite crystal. These specimens are valued by collectors because they clearly show the process of crystal overgrowth and later removal of the original mineral.

Questions about this specimen?
Send an email or call us: 314-341-1811.