Constituent
Name
Alunogen
IMA name
Alunogen
Class
non-silicate mineral
Compound type
sulfate
Constituent abundance in material
Relevance
main - major
Arrangement
in multi-phases
Mass fraction
0.1 $\pm$ 0.1
Chemical composition
Formula
$Al_2(SO_4)_3 \bullet 17(H_2O)$
Chemical formula
Al2(SO4)3•17(H2O)
Elemental formula
Al2 S3 O23 (O-)6 H34
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Al$ Aluminium element 2 constituent element main
$(SO_4)^{2-}$ Sulfate anion chemical function 3 anionic radical main
$H_2O$ Water molecule 17 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 $Al_{2}O_{3}$ $H_{2}O$ $SO_{3}$
Mass fraction (%) 15.72 47.23 37.04

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.45

Dana

Major class
sulfates, chromates, selenates (VI)
Class
hydrated acid and sulfates (29)
Type
where (A)2(XO4)3.x(H2O) (29.08)
Group
-Alunogen- group (29.08.06)
Code
29.08.06.01
Phase type
crystalline
Crystal system
triclinic
Crystal class
pinacoidal
Crystal class symbol
-1 (Ci)
Crystal spacegroup
P-1
Molar mass
648.41 $g/mol$
Density
1.65 - 1.78 $g/cm^3$
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.0070
Refraction index $n_{\alpha}$
1.473
Refraction index $n_{\beta}$
1.474
Refraction index $n_{\gamma}$
1.48
Dispersion V
none
Color
white, yellowish white, reddish white, yellowish white
Diaphaneity
transparent
Luster
vitreous