Input interpretation
bytownite (mineral)
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General properties
alternate names | ab20 | plagioclase (An70-90) formula | (Ca, Na)(Si, Al)_4O_8
Basic properties
density | 2.71 g/cm^3 transparency | translucent | transparent birefringence | 0.0105 luster | subvitreous Mohs hardness | 6.25 streak | white magnetism | nonmagnetic color | colorless | gray | white fracture | uneven molar mass | 275 g/mol (grams per mole)
Units
Mineral identifiers
Strunz ID | VIII/J.07-60 Dana ID | 76.1.3.5
Crystallographic properties
crystal system | triclinic crystal class | 1 unit cell volume | 1239 Å^3 (cubic ångströms) d-spacing | 3.2 Å (ångströms) | 3.75 Å (ångströms) | 4.03 Å (ångströms) intensity | 100% | 80% | 80% molecules per unit cell | 7 molecules per cell 2V angle | 7 π/15 radians≈84° (degrees) refractive indices | 1.568 | 1.573 | 1.578 | 0 | 0 | 0 dispersion | r > v | strong unit cell lengths | 8.17 Å (ångströms) | 12.85 Å (ångströms) | 13.16 Å (ångströms) unit cell angles | 93.5° (degrees) | 116° (degrees) | 90.83° (degrees)
Wikipedia summary
Bytownite is a calcium rich member of the plagioclase solid solution series of feldspar minerals with composition between anorthite and labradorite. It is usually defined as having between 70 and 90%An (formula: (Ca_(0.7-0.9), Na_(0.3-0.1))). Like others of the series, bytownite forms grey to white triclinic crystals commonly exhibiting the typical plagioclase twinning and associated fine striations.