Mineral phase
IMA name
Cinnabar
Secondary names
Cinabre
CAS number
1344-48-5
Class
non-silicate mineral
Compound type
sulfide
Formula
$\alpha-HgS$
Chemical formula
HgS
Elemental formula
Hg S
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Hg$ Mercury element 1 constituent element main
$S$ Sulfur element 1 constituent element main

Strunz

Class
sulfides - sufosalts (02)
Division
metal sulfides, M:S = 1:1 (and similar) (02.C)
Family
With Sn, Pb, Hg, etc. (02.CD)
Code
02.CD.15a

Dana

Major class
sulfides (II)
Class
sulfides - including selenides and tellurides (02)
Type
where Am Bn Xp, with m:p=1:1 (02.08)
Group
-Cinnabar- group (02.08.14)
Code
02.08.14.01
Phase type
crystalline
Crystal system
trigonal
Crystal class
trapezohedral
Crystal class symbol
32 (D3)
Crystal spacegroup
P3(1)21
Molar mass
232.66 $g/mol$
Density
8.1 $g/cm^3$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-solid Metacinnabar below 617K (344°C) at 1 bar
Refringence type
uniaxial
Refringence sign
positive
Birefringence
0.351
Refraction index $n_o$ (w)
2.905
Refraction index $n_e$ (e)
3.256
Pure color
red
Color
lead gray, brown, brown pink, vermilion, gray
Diaphaneity
translucent to opaque
Luster
adamantine