Constituent
- Name
- Alum-(K)
- IMA name
- Alum-(K)
- Class
- non-silicate mineral
- Compound type
- sulfate
- Relevance
- main - major
- Arrangement
- in multi-phases
- Mass fraction
- 0.27 $\pm$ 0.1
- Formula
- $KAl(SO_4)_2 \bullet 12(H_2O)$
- Chemical formula
- KAl(SO4)2•12(H2O)
- Elemental formula
- (K+) Al S2 O16 (O-)4 H24
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula $K_{2}O$ $Al_{2}O_{3}$ $H_{2}O$ $SO_{3}$ Mass fraction (%) 9.93 10.75 45.57 33.75
Strunz
- Class
- sulfates - chromates - molybdates - tungstates (07)
- Division
- sulfates (selenates, etc.) without additional anions, with H2O (07.C)
- Family
- with medium-sized and large cations (07.CC)
- Code
- 07.CC.20
Dana
- Major class
- sulfates, chromates, selenates (VI)
- Class
- hydrated acid and sulfates (29)
- Type
- where AB(XO4)2.x(H2O) (29.05)
- Group
- Alum group (29.05.05)
- Code
- 29.05.05.01
- Phase type
- crystalline
- Crystal system
- isometric (cubic)
- Crystal class
- diploidal
- Crystal class symbol
- m-3 (Th)
- Crystal spacegroup
- Pa-3
- Molar mass
- 474.39 $g/mol$
- Density
- 1.76 $g/cm^3$
- Refringence type
- isotropic
- Refraction index $n_{\alpha}$
- 1.453
- Color
- colorless, white
- Diaphaneity
- transparent
- Luster
- vitreous