Mineral phase
IMA name
Anhydrite
Type
Class
non-silicate mineral
Compound type
sulfate
Chemical composition
Formula
$CaSO_4 $
Chemical formula
CaSO4
Elemental formula
Ca S O4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Ca$ Calcium element 1 constituent element main
$S$ Sulfur element 1 constituent element main
$O$ Oxygen element 4 constituent element main
Chemical functions
  Function Number
$(SO_4)^{2-}$ 1
Chemical bonds
  Bond Number
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Oxides
Formula $CaO$ $SO_{3}$
Mass fraction (%) 41.19 58.81

Strunz

Class
sulfates - chromates - molybdates - tungstates (07)
Division
sulfates (selenates, etc.) without additional anions, without H2O (07.A)
Family
with only large cations (07.AD)
Code
07.AD.30

Dana

Major class
sulfates, chromates, selenates (VI)
Class
anhydrous acid and sulfates (28)
Type
where (A++)XO4 (28.03)
Group
-Anhydrite- group (28.03.02)
Code
28.03.02.01
Phase type
crystalline
Crystal system
orthorhombic
Crystal class
dipyramidal
Crystal class symbol
mmm (D2h)
Crystal spacegroup
Cmcm
Molar mass
136.14 $g/mol$
Density
2.96-2.98 $g/cm^3$
State NTP
solid
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.04 - 0.045
Refraction index $n_{\alpha}$
1.569 - 1.573
Refraction index $n_{\beta}$
1.574 - 1.579
Refraction index $n_{\gamma}$
1.609 - 1.618
Dispersion V
36-45
Pure color
colorless
Color
colorless, white, bluish white, violet white, dark gray
Diaphaneity
transparent to translucent
Luster
vitreous
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