Metacinnabar

This metacinnabar formed in mercury-rich hydrothermal deposits, where sulfur and mercury crystallized under higher-temperature conditions than its more common relative, cinnabar. The Diablo Mercury Mine, part of California’s historic mercury mining region, produced a variety of unusual mercury minerals from altered volcanic terrain.

Dark metallic in appearance and uncommon in occurrence, this specimen reflects the unique chemistry of mercury ore systems and preserves a piece of California’s early mining history.