A mineral of mercury sulphide (HgS), the chief ore of mercury. It consists of small, red, soft crystals formed in hydrothermal veins and volcanic deposits, and is used in the mineral pigment vermilion.
(Discuss)| Cinnabar | |
|---|---|
| General | |
| Category | Mineral |
| Chemical formula | mercury(II) sulfide, HgS |
| Identification | |
| Color | Brownish-red |
| Crystal habit | Rhombohedral to tabular. Granular to massive |
| Crystal system | Hexagonal |
| Cleavage | Prismatic, perfect |
| Fracture | Uneven to subconchoidal |
| Mohs Scale hardness | 2-2.5 |
| Luster | Adamantine to dull |
| Refractive index | Transparent to opaque |
| Pleochroism | N/A |
| Streak | Scarlet |
| Specific gravity | 8 - 8.2 g/cm³ |
| Fusibility | ? |
| Solubility | 3.10-26 g per 100 mL water |
| Major varieties | |
| None | |
Cinnabar, sometimes written cinnabarite, is a name applied to red mercury(II) sulfide (HgS), or native vermilion, the common ore of mercury.
Properties
Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color.
Cinnabar is found in all localities that yield mercury, notably Almadén (Spain), New Almaden (California), Idrija (Slovenia), New Idria (California), Landsberg, near Obermoschel in the Palatinate, Ripa, at the foot of the Apuan Alps (Tuscany), the mountain Avala (Serbia), Huancavelica (Peru), Terlingua (Texas), and the province of Guizhou in China, where fine crystals have been obtained.
Mining and extraction of mercury
Cinnabar was mined by the Roman Empire both as a pigment and for its mercury content, and it has been the main ore of mercury throughout the centuries.
Because of the high toxicity of mercury, both the mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning.
Medicinal use
Although cinnabar is known to be highly toxic, it is nevertheless used (as is arsenic), in powdered form mixed with water, in traditional Chinese medicine (TCM).
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