Constituent Plagioclase | SSHADE

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Constituent

Name: Plagioclase
IMA name: Feldspars group

Class: silicate mineral
Compound type: tektosilicate
Comments: K-Na series of Feldspar

Constituent abundance in material

Relevance: main - major
Arrangement: inclusion

Chemical composition

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

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Ca$	Calcium	element	0 - 1		constituent element	main
	$Na$	Sodium	element	0 - 1		constituent element	main
	$K$	Potassium	element	0 - 1		constituent element	main
	$Ba$	Barium	element	0 - 1		constituent element	main
	$Al$	Aluminium	element	1 - 2		constituent element	main
	$Si$	Silicon	element	2 - 3		constituent element	main
	$O$	Oxygen	element	8		constituent element	main

Composition comments: Limited solid solution beetween Ca-K - Common impurities: Mg, Fe, Rb

Oxides composition

Oxides

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

Classifications

Strunz

Class: silicates (09)
Division: tektosilicate without zeolitic H2O (09.F)
Family: 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

Crystallography

Crystal system: various
Crystal class: various
Crystal class symbol: various
Crystal spacegroup: various

Texture: polycrystalline

Physical properties

Molar mass: 263.02 - 278.33 $g/mol$
Density: 2.56 - 2.76 $g/cm^3$

Optical properties

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