Metacinnabar is the cubic form of mercury sulfide (HgS). It is the high temperature form and trimorphous with cinnabar (trigonal structure) and the higher temperature hypercinnabar (hexagonal structure). It occurs with cinnabar in mercury deposits and is associated with native mercury, wurtzite, stibnite, marcasite, realgar, calcite, barite, chalcedony and hydrocarbons.[2]

Metacinnabar
General
CategorySulfide mineral
Formula
(repeating unit)
HgS
IMA symbolMcin[1]
Strunz classification2.CB.05a
Crystal systemCubic
Crystal classHextetrahedral (43m)
H-M symbol: (4 3m)
Space groupF43m
Unit cella = 5.8717(5) Å; Z = 4
Structure
Jmol (3D)Interactive image
Identification
ColorGrayish black
Crystal habitMassive, rarely as tetrahedral crystals, as incrustations
TwinningCommon as lamellae on {111}
CleavageNone
FractureSubconchoidal
TenacityBrittle
Mohs scale hardness3
LusterMetallic
StreakBlack
DiaphaneityOpaque
Specific gravity7.7–7.8
References[2][3][4]

It was first described in 1870 for an occurrence in the Redington mine, Knoxville, Napa County, California.[3][4]

References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Metacinnabar in the Handbook of Mineralogy
  3. ^ a b Metacinnabar on Mindat.org
  4. ^ a b Metacinnabar data on Webmineral