2.7" Vibrant-Red Cinnabar with Calcite - Cocineras Mine

This is a beautiful association of vibrant-red cinnabar and calcite crystals, collected from the Cocineras Mine in the Santa Eulalia mining district of Chihuahua, Mexico. Some gypsum can be found scattered throughout this specimen as well.

Cinnabar is a mercury sulfide mineral with the chemical formula HgS. It is a vibrant red color and is an important ore of mercury. It is primarily found as fillings within gaps of rocks and coating rocks as a result of ascending hydrothermal activity. While cinnabar is typically massive in habit, large crystals have been found on rare occasions. The striking red color of cinnabar made for an attractive pigment, but its use as a pigment was halted following discovery of its toxic properties.

Toxicity Warning: The mercury content of cinnabar can be harmful if absorbed into the bloodstream by inhalation or ingestion. The crystals do not pose a health hazard just sitting on a shelf, but it is highly recommended that you wear gloves and/or wash your hands after handling.

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.

Cinnabar, Gypsum & Calcite
Cocineras Mine, Santa Eulalia Mining District, Chihuahua, Mexico
2.7 x 2.3"