Constituent
- Name
- Plagioclase
- IMA name
- Feldspars group
- Class
- silicate mineral
- Compound type
- tektosilicate
- Comments
- K-Na series of Feldspar
- Relevance
- main - major
- Arrangement
- unknown
- Mass fraction
- 0.5 $\pm$ 0.3
- Formula
- $(K,Na,Ca,Ba)(Al,Si)AlSi_2O_8$
- Chemical formula
- (Ca,Na,K,Ba)(Al,Si)AlSi2O8
- Elemental formula
- (Ca)0-1 (Na)0-1 (K)0-1 (Ba)0-1 (Al)1-2 (Si)2-3 O8
- Isotope mixture type
- terrestrial abundance
- Composition comments
- Limited solid solution beetween Ca-K - Common impurities: Mg, Fe, Rb
- Oxides
-
Formula $CaO$ $Na_{2}O$ $K_{2}O$ $BaO$ $Al_{2}O_{3}$ $SiO_{2}$ Mass fraction (%)
Strunz
- Class
- silicates (09)
- Division
- tektosilicate without zeolitic H2O (09.F)
- Family
- Tektosilicates without additional non-tetrahedral anions, (Al,B):Si = 1:1 (09.FA)
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
- polycrystalline
- Molar mass
- 263.02 - 278.33 $g/mol$
- Density
- 2.56 - 2.76 $g/cm^3$
- Refringence type
- biaxial
- Refringence sign
- positive or negative
- Birefringence
- 0.005 - 0.012
- Refraction index $n_{\alpha}$
- 1.518 - 1.576
- Refraction index $n_{\beta}$
- 1.522 - 1.583
- Refraction index $n_{\gamma}$
- 1.523 - 1.588
- Dispersion V
- weak to relatively strong
- Color
- colorless, white, gray, greenish, bluish green, grayish yellow, white, pink
- Diaphaneity
- transparent to subtranslucent
- Luster
- vitreous