Class

non-silicate mineral

Compound type

sulfate

Chemical functions

	Function	Number
	$(SO_4)^{2-}$	1

Chemical bonds

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

Oxides

Formula	$Na_{2}O$	$SO_{3}$
Mass fraction (%)	43.63	56.37

Strunz

Class

sulfates - chromates - molybdates - tungstates (07)

Division

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

Family

with medium-sized and large cations (07.AC)

Code

07.AC.25

Dana

Major class

sulfates, chromates, selenates (VI)

Class

anhydrous acid and sulfates (28)

Type

where (A+)2XO4 (28.02)

Group

-Thenardite- group (28.02.03)

Code

28.02.03.01

Phase type

crystalline

Crystal system

orthorhombic

Crystal class

dipyramidal

Crystal class symbol

mmm (D2h)

Crystal spacegroup

Fddd

Molar mass

142.04 $g/mol$

Density

2.67-2.7 $g/cm^3$

Refringence type

biaxial

Refringence sign

positive

Birefringence

0.013

Refraction index $n_{\alpha}$

1.471

Refraction index $n_{\beta}$

1.477

Refraction index $n_{\gamma}$

1.484

Dispersion V

83

Color

white, grayish white, yellowish white, reddish white, brownish white

Diaphaneity

transparent

Luster

vitreous