Mineral phase
- IMA name
- Pentahydrite
- Secondary names
- Allenite
- IMA Code
- Phy
- Class
- non-silicate mineral
- Compound type
- sulfate
- Formula
- MgSO4∙5H2O
- Chemical formula
- MgSO4•5H2O
- Elemental formula
- (Mg2+) S O7 (O-)2 H10
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula MgO SO_{3} H_{2}O Mass fraction (%) 19.15 38.05 42.8
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.20
Dana
- Major class
- sulfates, chromates, selenates (VI)
- Class
- hydrated acid and sulfates (29)
- Type
- where AXO4.x(H2O) (29.06)
- Group
- Chalchanthite group (Pentahydrates, triclinic: P-1) (29.06.07)
- Code
- 29.06.07.03
- Phase type
- crystalline
- Crystal system
- triclinic
- Crystal class
- pinacoidal
- Crystal class symbol
- -1 (Ci)
- Crystal spacegroup
- P-1
- Molar mass
- 210.45 g/mol
- Density
- 1.9 g/cm^3
- State NTP
- solid
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.011 - 0.023
- Refraction index n_{\alpha}
- 1.482 - 1.495
- Refraction index n_{\beta}
- 1.492 - 1.512
- Refraction index n_{\gamma}
- 1.493 - 1.518
- Pure color
- colorless
- Color
- colorless, white, light blue, light greenish blue
- Diaphaneity
- transparent to translucent
- Luster
- vitreous