Mineral phase
IMA name
Albite
Secondary names
Clevelandite
Class
silicate mineral
Compound type
tektosilicate
Comments
Albite: name by extension in the range Ca=0-10%, K=0-10% of (Na,Ca,K)Al2Si2O8
Formula
NaAlSi3O8
Chemical formula
NaAlSi3O8
Elemental formula
Na Al Si3 O8
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
Na Sodium element 1 constituent element main
Al Aluminium element 1 constituent element main
Si Silicon element 3 constituent element main
O Oxygen element 8 constituent element main
Composition comments
Typical formula: Na0.95Ca0.05Al1.05Si2.95O8 - Common replacement: Ca, K - Common impurities: Mg
Oxides
Formula Na2O CaO K2O Al2O3 SiO2
Mass fraction (%) 12.26 20.35 67.39
Oxides comments
frequently also Na2O ~1%

Strunz

Class
silicates (09)
Division
tektosilicate without zeolitic H2O (09.F)
Family
without additional non-tetrahedral anions, (Al,B):Si = 1:1 (09.FA)
Code
09.FA.35

Dana

Major class
silicates (VIII)
Class
tectosilicate Al-Si framework (76)
Type
with Al-Si frameworks (76.01)
Group
Plagioclase series (76.01.03)
Code
76.01.03.01
Phase type
crystalline
Crystal system
triclinic
Crystal class
pinacoidal
Crystal class symbol
-1 (Ci)
Crystal spacegroup
P-1
Molar mass
263.02 g/mol
Density
2.61 - 2.63 g/cm3
State NTP
solid
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.009 - 0.010
Refraction index nα
1.528 - 1.533
Refraction index nβ
1.532 - 1.537
Refraction index nγ
1.538 - 1.542
Dispersion V
r < v; weak (low)
Pure color
white
Color
white, gray, greenish gray, bluish green
Diaphaneity
transparent to subtranslucent
Luster
vitreous