Astrakanite

Astrakanite
Mineralogical name	Astrakanite, Bloedite
Chemical name	Sodium magnesium sulfate
Trivial name
Chemical formula	Na2Mg(SO4)2•4H2O
Other forms
Crystal system	monoclinic
Crystal structure
Deliquescence humidity 20°C
Solubility (g/l) at 20°C
Density (g/cm³)	2.23 g/cm3
Molar volume	150.0 cm3/mol
Molar weight	334.48 g/mol
Transparency	transparent
Cleavage	none observed
Crystal habit
Twinning
Phase transition
Chemical behavior
Comments
Crystal Optics
Refractive Indices	nx = 1.483 ny = 1.486 nz = 1.487
Birefringence	Δ = 0.004
Optical Orientation	biaxial negative
Pleochroism
Dispersion	0.71°
Used Literature
[Dana:1951]Title: Dana's System of Mineralogy Author: Dana J.D. [JCPDS:1991]Title: JCPDS Powder Diffraction File 2 (PDF-2)

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Literature

[Dana:1951]	Dana E.S. (eds.) Dana J.D. (1951): Dana's System of Mineralogy, 7, Wiley & Sons
[JCPDS:1991]	(1991): JCPDS Powder Diffraction File 2 (PDF-2).

A phase is a physically distinctive form of matter and is characterized by having relatively uniform chemical and physical properties.