Cinnabar (
German Zinnober), sometimes written
cinnabarite, is a name applied to red
mercuric sulphide (HgS), or native vermilion, the common
ore of mercury. The name comes from the
Greek, used by
Theophrastus, and probably applied to several distinct substances. Cinnabar is generally found in a massive, granular or earthier 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. Cinnabar has higher
refractive power than any other known mineral, its mean index for
sodium light being 3 ~O2, whilst the index for diamond—a substance of remarkable refraction—is only 2~42. 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), Idrija[?] (Slovenia), Landsberg[?], near Ober-Moschel[?] in the Palatinate, Ripa[?], at the foot of the Apuan Alps[?] (Tuscany), the mountain Avala (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 Idrija 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.*)
based on an article from 1911 Encyclopedia Britannica
See also: List of minerals
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