Metacinnabar

HgS
c 2001-2005 Mineral Data Publishing, version 1Crystal Data: Cubic. Point Group: 43m. Commonly massive; rarely as small (to 1 mm)
tetrahedral crystals having rough faces. Twinning: Common on {111}, forming lamellae inpolished section.
Physical Properties: Fracture: Subconchoidal. Tenacity: Brittle. Hardness = 3
VHN = n.d. D(meas.) = 7.65 D(calc.) = 7.63
Optical Properties: Opaque. Color: Grayish black; in polished section, grayish white.
Streak: Black. Luster: Metallic. Pleochroism: Weak, rarely. Anisotropism: Very weak, rarely.
R: (400) 28.4, (420) 27.6, (440) 26.8, (460) 26.3, (480) 25.9, (500) 25.6, (520) 25.4, (540) 25.2,(560) 25.1, (580) 25.0, (600) 24.9, (620) 24.9, (640) 24.8, (660) 24.7, (680) 24.7, (700) 24.7
Cell Data:

Space Group: F 43m. a = 5.8717(5)Z=4

X-ray Powder Pattern: Synthetic.
3.378 (100), 2.068 (55), 1.7644 (45), 2.926 (35), 1.3424 (12), 1.6891 (10), 1.3085 (10)Chemistry:HgZnCdFeSe
S

(1)
79.73
4.23
trace
1.08
14.58(2)
67.45
3.10
11.72
0.2
15.63

(3)
81.33

(4)
86.22

6.49
10.30

13.78

Total 99.62
98.10
98.12
100.00(1) Guadalcázar, Mexico; corresponds to (Hg0.85 Zn0.14 )Σ=0.99 (S0.97 Se0.03 )Σ=1.00 . (2) Uland area,Russia; corresponds to (Hg0.69 Cd0.21 Zn0.10 Fe0.01 )Σ=1.01 S1.00 . (3) San Onofre, Mexico; corresponds
to Hg1.00 (S0.80 Se0.20 )Σ=1.00 . (4) HgS.
Polymorphism & Series:
Mineral Group:
Occurrence:

Trimorphous with cinnabar and hypercinnabar.

Sphalerite group.

In mercury deposits formed under low-temperature near-surface conditions.

Association: Cinnabar, mercury, wurtzite, stibnite, marcasite, realgar, calcite, barite,“chalcedony”, hydrocarbons.
Distribution: Not uncommon in mercury deposits; may be a principal ore mineral. In the USA,in California, in the Redington mine [TL] and other properties, near Knoxville, Napa Co.; atthe Ryne mine, Mt. Diablo, Contra Costa Co.; from New Almaden, Santa Clara Co.; at Skaggs
Springs, Sonoma Co.; from New Idria, San Benito Co.; and many other places. At Terlingua,Brewster Co., Texas; from Marysvale, Ohio district, Piute Co., Utah; and in the Reward mines,Franklin, King Co., Washington. In Canada, from Read Island, Nanaimo mining division, BritishColumbia. In Mexico, at San Onofre, near Plateros, Zacatecas; also from Guadalcázar, San Luis
Potosı́. At Idrija (Idria), Slovenia. In Italy, from Levigliani, Tuscany. In Romania, at Baia Sprie(Felsőbánya). From Almadén, Ciudad Real Province, Spain. In the Uland area, Kurai ore zone,Altai Mountains, and other deposits in Russia. At Wen-Shan-Chang, Kweichow, and elsewhere inChina.
Name:

From the Greek for with, plus cinnabar, in allusion to its common association.

References: (1) Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy,(7th edition), v. I, 215–217. (2) Aurivillius, K. (1964) An X-ray and neutron diffraction studyof metacinnabarite. Acta Chem. Scand., 18, 1552–1553. (3) (1955) NBS Circ. 539, 4, 21–23.
(4) Criddle, A.J. and C.J. Stanley, Eds. (1993) Quantitative data file for ore minerals, 3rd ed.
Chapman & Hall, London, 367.
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