Mineral phase
IMA name
Natrolite
Type
Class
silicate mineral
Compound type
tektosilicate
Chemical composition
Formula
$Na_2(Al_2Si_3O_{10})\bullet2(H_2O)$
Chemical formula
Na2(Al2Si3O10)•2(H2O)
Elemental formula
Na2 Al2 Si3 O12 H4
Isotope mixture type
terrestrial abundance
  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
Molar mass
380.22 $g/mol$
Density
2.20 - 2.26 $g/cm^3$
State NTP
solid
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
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