Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Na$	Sodium	element	2		constituent element	main
	$Al$	Aluminium	element	2		constituent element	main
	$Si$	Silicon	element	3		constituent element	main
	$O$	Oxygen	element	12		constituent element	main
	$H$	Hydrogen	element	4		constituent element	main

Oxides

Formula	$Na_{2}O$	$Al_{2}O_{3}$	$SiO_{2}$	$H_{2}O$
Mass fraction (%)	16.3	26.82	47.41	9.48

Strunz

Class

silicates (09)

Division

tektosilicate with zeolitic H2O (09.G)

Family

Zeolites with T5O10 Units – The Fibrous Zeolites (09.GA)

Code

09.GA.05

Dana

Major class

silicates (VIII)

Class

tectosilicate zeolite group (77)

Type

true zeolites (77.01)

Group

Natrolite and related species (77.01.05)

Code

77.01.05.01

Phase type

crystalline

Crystal system

orthorhombic

Crystal class

pyramidal

Crystal class symbol

mm2 (C2v)

Crystal spacegroup

Fdd2

Refringence type

biaxial

Refringence sign

positive

Birefringence

0.0120-0.0130

Refraction index $n_{\alpha}$

1.473-1.489

Refraction index $n_{\beta}$

1.476-1.491

Refraction index $n_{\gamma}$

1.485-1.502

Dispersion V

Dispersion weak, r < v

Pure color

colorless

Color

White, Colorless, Red, Yellowish white, Reddish white

Diaphaneity

transparent to translucent

Luster

vitreous

Links

• Wikipedia
• Webmineral database
• Mindat
• Handbook of Mineralogy (Min. Soc. Am)