Difference between revisions of "Template:Feldspar"
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! colspan=2 | Feldspar | ! colspan=2 | Feldspar | ||
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− | | Chemical composition || Potassium, | + | | Chemical composition || Potassium, sodium and calcium-aluminum silicates<br /> |
− | I. K- | + | I. K-feldspar (KALSi<sub>3</sub>0<sub>8</sub>)<br /> |
− | II . Plagioclase | + | II . Plagioclase feldspar (isomorphous) |
|- | |- | ||
− | | Crystal system || | + | | Crystal system || Monoclinic - triclinic |
|- | |- | ||
− | | Habit || | + | | Habit || Prismatic, often twinned |
|- | |- | ||
− | | Cleavage || | + | | Cleavage || Good to perfect |
|- | |- | ||
− | | Fracture || | + | | Fracture || Conchoidal |
|- | |- | ||
| Hardness || 6 | | Hardness || 6 | ||
|- | |- | ||
− | | Optic nature || | + | | Optic nature || Biaxial ± |
|- | |- | ||
− | | Refractive index || 1.52 - 1.53 (K- | + | | Refractive index || 1.52 - 1.53 (K-feldspar)<br /> |
− | 1. | + | 1.528 - 1.588 (plagioclase) |
|- | |- | ||
− | | Birefringence || 0.006 - 0.007 (K- | + | | Birefringence || 0.006 - 0.007 (K-feldspar)<br /> |
− | 0.008 - 0.011 ( | + | 0.008 - 0.011 (plagioclase) |
|- | |- | ||
− | | Specific gravity || 2.55 - 2,58 (K- | + | | Specific gravity || 2.55 - 2,58 (K-feldspar)<br /> |
− | 2.60 - 2.80 ( | + | 2.60 - 2.80 (plagioclase) |
|- | |- | ||
− | | Lustre || | + | | Lustre || Vitreous |
|} | |} | ||
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Latest revision as of 09:48, 8 March 2009
Feldspar | |
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Chemical composition | Potassium, sodium and calcium-aluminum silicates I. K-feldspar (KALSi308) |
Crystal system | Monoclinic - triclinic |
Habit | Prismatic, often twinned |
Cleavage | Good to perfect |
Fracture | Conchoidal |
Hardness | 6 |
Optic nature | Biaxial ± |
Refractive index | 1.52 - 1.53 (K-feldspar) 1.528 - 1.588 (plagioclase) |
Birefringence | 0.006 - 0.007 (K-feldspar) 0.008 - 0.011 (plagioclase) |
Specific gravity | 2.55 - 2,58 (K-feldspar) 2.60 - 2.80 (plagioclase) |
Lustre | Vitreous |