Cinnabar

The only common ore of mercury is the mineral cinnabar, a mercuric sulfide, HgS. It occurs as bright-red crusts, granular masses, or earthy coatings. Cinnabar yields a scarlet streak and displays perfect cleavage in one direction. The luster is adamantine to metallic. It occurs in areas of recent volcanic activity, where it was probably precipitated from alkaline solutions in veins, hot-spring deposits, and porous volcanic rocks. It has been mined for more than 2,500 years at Almaden, Spain, which has the world's most important deposit. Used as an ornamental stone, and in vermillion paint, faceted crystal is rare @ $500 pc.