Constituent
Name
Coquimbite
IMA name
Coquimbite
Class
non-silicate mineral
Compound type
sulfate
Constituent abundance in material
Relevance
main - minor
Arrangement
in multi-phases
Mass fraction
0.01 $\pm$ 0.1
Chemical composition
Formula
$Fe^{3+}_2(SO_4)_3 \bullet 9(H_2O)$
Chemical formula
(Fe3+)2(SO4)3•9(H2O)
Elemental formula
(Fe3+)2 S3 O15 (O-)6 H18
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Fe^{3+}$ Iron(III) cation element 2 constituent cation main
$(SO_4)^{2-}$ Sulfate anion chemical function 3 anionic radical main
$H_2O$ Water molecule 9 hydration main
Chemical functions
  Function Number Relevance
$(SO_4)^{2-}$ 3
$R-OH$ 2 main
Chemical bonds
  Bond Number Relevance
$-O-H$ 2 main
$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$ 4
Oxides
Formula $Fe_{2}O_{3}$ $H_{2}O$ $SO_{3}$
Mass fraction (%) 28.41 28.85 42.74

Strunz

Class
sulfates - chromates - molybdates - tungstates (07)
Division
sulfates (selenates, etc.) without additional anions, with H2O (07.C)
Family
with only medium-sized cations (07.CB)
Code
07.CB.50

Dana

Major class
sulfates, chromates, selenates (VI)
Class
hydrated acid and sulfates (29)
Type
where (A)2(XO4)3.x(H2O) (29.08)
Group
-Coquimbite- group (29.08.03)
Code
29.08.03.01
Phase type
crystalline
Crystal system
trigonal
Crystal class
ditrigonal-scalenohedral
Crystal class symbol
-3m (D3d)
Crystal spacegroup
P-31c
Molar mass
562.02 $g/mol$
Density
2 - 2.1 $g/cm^3$
Refringence type
uniaxial
Refringence sign
positive
Birefringence
0.007
Refraction index $n_{\alpha}$
1.55
Refraction index $n_{\beta}$
1.557
Color
greenish white, bluish white, light violet, yellowish white, brownish white
Diaphaneity
transparent
Luster
vitreous