| 76th | Top minerals |
| Cinnabar | |
|---|---|
 Cinnabar on Dolomite |
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| General | |
| Category | Mineral |
| Chemical formula | mercury(II) sulfide, HgS |
| Identification | |
| Color | Brownish-red |
| Crystal habit | Rhombohedral to tabular. Granular to massive |
| Crystal system | Trigonal – Trapezohedral |
| Cleavage | Prismatic, perfect |
| Fracture | Uneven to subconchoidal |
| Mohs scale hardness | 2-2.5 |
| Luster | Adamantine to dull |
| Streak | Scarlet |
| Specific gravity | 8.176 |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 2.905 nε = 3.256 |
| Birefringence | δ = 0.351 |
| Solubility | 1.04 x 10-25 g per 100 ml water (Ksp at 25°C = 2 x 10-32)[1] |
| References | [2][3][4] |
Cinnabar, (cinnabarite, red mercury(II) sulfide (HgS), native vermilion), is the common ore of mercury. The name comes from κινναβαρι (kinnabari), a Greek word most likely applied by Theophrastus to several distinct substances. Other sources say the word comes from the Persian زینجیفرح zinjifrah, a word of uncertain origin. In Latin it was sometimes known as minium, meaning also "red lead", though both of these terms now refer uniquely to lead tetroxide.
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HgS adopts two structures, i.e. it is dimorphous.[5] The more stable form is cinnabar, which has a structure akin to that for HgO: each Hg center has two short Hg-S bonds (2.36 Å), and four longer Hg---S contacts (3.10, 3.10, 3.30, 3.30 Å). The black form of HgS has the zinc blende structure.
Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color.[6] It occasionally occurs, however, in crystals with a non-metallic adamantine luster. Cinnabar has a rhombohedral bravais lattice, and belongs to the hexagonal crystal system, trigonal division. Its crystals grow usually in a massive habit, though they are sometimes twinned. The twinning in cinnabar is distinctive and forms a penetration twin that is ridged with six ridges surrounding the point of a pyramid. It could be thought of as two scalahedral crystals grown together with one crystal going the opposite way of the other crystal. The hardness of cinnabar is 2–2.5, and its specific gravity 8.1.
Cinnabar resembles quartz in its symmetry and certain of its optical characteristics. Like quartz, it exhibits birefringence. It has the highest refractive power of any mineral. Its mean index for sodium light is 3.08,[7] whereas the index for diamond—a substance of remarkable refraction— is 2.42 and that for gallium (III) arsenide (GaAs) is 3.93.
Generally cinnabar occurs as a vein-filling mineral associated with recent volcanic activity and alkaline hot springs. Cinnabar is deposited by epithermal ascending aqueous solutions (those near surface and not too hot) far removed from their igneous source.
It is associated with native mercury, stibnite, realgar, pyrite, marcasite, opal, quartz, chalcedony, dolomite, calcite and barite.[2]
Cinnabar is found in all localities that yield mercury, notably Puerto Princesa (Philippines); Almadén (Spain); New Almaden (California); Hastings Mine and St. John's Mine, Vallejo, California;[8] Idrija (Slovenia); New Idria (California); Giza, Egypt; Landsberg, near Obermoschel in the Palatinate; Ripa, at the foot of the Apuan Alps and in the Mount Amiata (Tuscany); the mountain Avala (Serbia); Huancavelica (Peru); Murfreesboro, Arkansas; Terlingua (Texas); and the province of Guizhou in China, where fine crystals have been obtained.
Cinnabar is still being deposited at the present day from the hot waters of Sulphur Bank Mine in California and Steamboat Springs, Nevada.
Cinnabar was mined since Neolithic Age (Martín-Gil et al). During the Roman Empire it was mined both as a pigment (Vitruvius, DA VII; IV-V) (Pliny, HN; XXXIII, XXXVI-XLII) and for its mercury content (Pliny HN; XXXIII, XLI), and it has been the main source of mercury throughout the centuries.
To produce liquid (quicksilver) mercury, crushed cinnabar ore is roasted in rotary furnaces. Pure mercury separates from sulfur in this process and easily evaporates. A condensing column is used to collect the liquid metal, which is most often shipped in iron flasks.
Cinnabar has been used for its color in the new world since the Olmec culture.[9] Cinnabar was often used in royal burial chambers during the peak of Mayan civilization. The red stone was inserted into limestone sarcophagi, both as a decoration and, more importantly, to deter vandals and thieves with its well-known toxicity.[10]
The most popularly known use of cinnabar is in Chinese carved lacquerware, a technique that apparently originated in the Song Dynasty.[11] The danger of mercury poisoning may be reduced in ancient lacquerware by entraining the powdered pigment in lacquer,[12] but could still pose an environmental hazard if the pieces were accidentally destroyed. In the modern jewelry industry, the toxic pigment is replaced by a resin-based polymer that approximates the appearance of pigmented lacquer.
In the Byzantine Empire, the Emperor and certain privileged bishops (such as the Ecumenical Patriarch and the Archbishop of Cyprus) were allowed the exclusive right of signing their names with ink colored vermilion by the addition of cinnabar.[citation needed]
Despite its toxicity, cinnabar has historically been used in traditional Chinese medicine, where it is called zhūshā (朱砂).
CINNABAR (Ger. Zinnober), sometimes written cinnabarite, a name applied to red mercuric sulphide (HgS), or native vermilion, the common ore of mercury. The name comes from the Greek «cvva(3ape, used by Theophrastus, and probably applied to several distinct substances. Cinnabar is generally found in a massive, granular or earthy form, of bright red colour, but it occasionally occurs in crystals, with a metallic adamantine lustre. The crystals belong to the hexagonal system, and are generally of rhombohedral habit, sometimes twinned. Cinnabar presents remarkable resemblance to quartz in its symmetry and optical characters. Like quartz it exhibits circular polarization, and A. Des Cloizeaux showed that it possessed fifteen times the rotatory power of quartz (see Polarization of light). Cinnabar has higher refractive power than any other known mineral, its mean index for sodium light being 3.02, whilst the index for diamond - a substance of remarkable refraction - is only 2.4 2 (see Refraction). The hardness of cinnabar is 3, and its specific gravity 8.998.
Cinnabar is found in all localities which yield quicksilver, notably Almaden (Spain), New Almaden (California), Idria (Austria), Landsberg, near Ober-Moschel in the Palatinate, Ripa, at the foot of the Apuan Alps (Tuscany), the mountain A y ala (Servia), Huancavelica (Peru), and the province of Kweichow in China, whence very fine crystals have been obtained. Cinnabar is in course of deposition at the present day from the hot waters of Sulphur Bank, in California, and Steamboat Springs, Nevada.
Hepatic cinnabar is an impure variety from Idria in Carniola, in which the cinnabar is mixed with bituminous and earthy matter.
Metacinnabarite is a cubic form of mercuric sulphide, this compound being dimorphous.
For a general description of cinnabar, see G. F. Becker's Geology of the Quicksilver Deposits of the Pacific Slope, U.S. Geol. Surv. Monographs, No. xiii. (1888). (F. W. R.*)
Cinnabar is a mineral. It is the main ore of mercury and is made up of the chemical mercuric sulphide (HgS). Cinnabar exists in two crystal forms. Red cinnabar is used for the pigment vermilion. It is poisonous, and may go black with age. The other crystal form is black, and does not react chemically to anything except strong acids. Cinnabar has a Mohs hardness of 2-2.5.
   | MSDS for cinnabar - Safety (MSDS) data for mercuric sulphide |
| | Cinnabar visual reference - CINNABAR (Mercury Sulfide) |
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