Class

silicate mineral

Compound type

tektosilicate

Comments

from Vogt et al. (2002)
K-Na series of Feldspar

Composition comments

Ca has limited solid solution - Common replacements: Ba - Common impurities: Mg, Fe, Rb, H2O

Oxides

Formula	$K_{2}O$	$Na_{2}O$	$CaO$	$Al_{2}O_{3}$	$SiO_{2}$
Mass fraction (%)

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.30

Dana

Major class

silicates (VIII)

Class

tectosilicate Al-Si framework (76)

Type

with Al-Si frameworks (76.01)

Group

N/A (N/A)

Phase type

crystalline

Crystal system

various

Crystal class

various

Crystal class symbol

various

Crystal spacegroup

various

Texture

unknown

Molar mass

263.02 - 278.33 $g/mol$

Density

2.56 - 2.63 $g/cm^3$

Refringence type

biaxial

Refringence sign

positive or negative

Birefringence

0.005 - 0.010

Refraction index $n_{\alpha}$

1.518 - 1.533

Refraction index $n_{\beta}$

1.522 - 1.537

Refraction index $n_{\gamma}$

1.523 - 1.542

Dispersion V

weak to relatively strong

Color

colorless, white, gray, greenish, bluish green, grayish yellow, white, pink

Diaphaneity

transparent to subtranslucent

Luster

vitreous