Mineral phase
- IMA name
- Hexahydrite
- IMA Code
- Hhy
- Class
- non-silicate mineral
- Compound type
- sulfate
- Formula
- MgSO4∙6H2O
- Chemical formula
- MgSO4•6H2O
- Elemental formula
- (Mg2+) S O8 (O-)2 H12
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula MgO SO_{3} H_{2}O Mass fraction (%) 17.64 35.05 47.31
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.25
Dana
- Major class
- sulfates, chromates, selenates (VI)
- Class
- hydrated acid and sulfates (29)
- Type
- where AXO4.x(H2O) (29.06)
- Group
- Hexahydrite group (Hexahydrates, monoclinic: C2/c) (29.06.08)
- Code
- 29.06.08.01
- Phase type
- crystalline
- Crystal system
- monoclinic
- Crystal class
- prismatic
- Crystal class symbol
- 2/m (C2h)
- Crystal spacegroup
- C2/c
- Molar mass
- 228.46 g/mol
- Density
- 1.76 g/cm^3
- State NTP
- solid
- Phase transitions
-
Phase transition type Other phases Temperature - Pressure solid-solid Kieserite below 42% RH solid-solid Epsomite above 51% RH - Phase transitions comments
- hydrates to Epsomite in humid air
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.030
- Refraction index n_{\alpha}
- 1.426
- Refraction index n_{\beta}
- 1.453
- Refraction index n_{\gamma}
- 1.456
- Pure color
- colorless
- Color
- colorless, white, greenish
- Diaphaneity
- transparent to opaque
- Luster
- vitreous