Cinnabar

Cinnabar is mercury sulfide - the primary ore of mercury and one of the most visually striking (and toxic) minerals collected. Its vivid vermillion-red color is unmistakable and has been prized as a pigment since antiquity. The Chinese used ground cinnabar (called 'zhu sha') for red lacquerware, ink, and ceremonial paint for over 3,000 years.

Cinnabar forms in low-temperature hydrothermal veins associated with recent volcanic activity and hot springs. The mercury is mobilized from deep crustal sources by hot fluids and deposited near the surface when temperatures and pressures drop. Almaden, Spain, has been the world's most important mercury mine for over 2,000 years - Roman prisoners were sent to work the mines, where mercury exposure was essentially a death sentence.

IMPORTANT SAFETY NOTE: Cinnabar contains mercury. While mercury sulfide is relatively stable (less dangerous than liquid mercury or mercury vapor), specimens should be handled with care. Never heat cinnabar, never grind it, never touch it and then touch your face. Wash hands after handling. Keep away from children. Display in enclosed cases. NEVER use for gem elixirs.

Cinnabar is identified by its vivid scarlet-red color, extremely high density (8.10 - feels very heavy), adamantine luster, and scarlet streak. No other common mineral is both this red and this dense.

Distinguish from realgar (arsenic sulfide - orange-red, much lighter), cuprite (copper oxide - darker red, different associations), and red jasper (much harder, much lighter). Cinnabar's extreme density combined with its specific scarlet color is essentially diagnostic.