Class

non-silicate mineral

Compound type

sulfate

Chemical functions

	Function	Number
	$(SO_4)^{2-}$	2

Chemical bonds

	Bond	Number
	$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$	4

Oxides

Formula	$Na_{2}O$	$CaO$	$SO_{3}$
Mass fraction (%)	22.28	20.16	57.56

Strunz

Class

sulfates - chromates - molybdates - tungstates (07)

Division

sulfates (selenates, etc.) without additional anions, without H2O (07.A)

Family

with only large cations (07.AD)

Code

07.AD.25

Dana

Major class

sulfates, chromates, selenates (VI)

Class

anhydrous acid and sulfates (28)

Type

with miscellaneous formulae (28.04)

Group

-Glauberite- group (28.04.02)

Code

28.04.02.01

Phase type

crystalline

Crystal system

monoclinic

Crystal class

prismatic

Crystal class symbol

2/m (C2h)

Crystal spacegroup

C2/c

Molar mass

278.18 $g/mol$

Density

2.7 - 2.85 $g/cm^3$

Refringence type

biaxial

Refringence sign

negative

Birefringence

0.021 - 0.022

Refraction index $n_{\alpha}$

1.507 - 1.515

Refraction index $n_{\beta}$

1.527 - 1.535

Refraction index $n_{\gamma}$

1.529 - 1.536

Dispersion V

strong, r > v

Color

colorless, gray, gray white, yellow, yellowish white

Diaphaneity

transparent to translucent

Luster

vitreous