Difference between revisions of "Template:Feldspar"

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! colspan=2 | Feldspar
 
! colspan=2 | Feldspar
 
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| Chemical composition || Potassium, Sodium and Calcium-Aluminium Silicates<br />
+
| Chemical composition || Potassium, sodium and calcium-aluminium silicates<br />
I. K-Feldspar (KALSi<sub>3</sub>0<sub>8</sub>)<br />
+
I. K-feldspar (KALSi<sub>3</sub>0<sub>8</sub>)<br />
II . Plagioclase Feldspar (isomorphous)
+
II . Plagioclase feldspar (isomorphous)
 
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|-
| Crystal system || monoclinic - triclinic
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| Crystal system || Monoclinic - triclinic
 
|-
 
|-
| Habit || prismatic, often twinned  
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| Habit || Prismatic, often twinned  
 
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|-
| Cleavage || good to perfect
+
| Cleavage || Good to perfect
 
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|-
| Fracture || conchoidal
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| Fracture || Conchoidal
 
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|-
 
| Hardness || 6
 
| Hardness || 6
 
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| Optic nature || biaxial - or +
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| Optic nature || Biaxial &plusmn;
 
|-
 
|-
| Refractive index || 1.52 - 1.53 (K-Feldspar)<br />
+
| Refractive index || 1.52 - 1.53 (K-feldspar)<br />
1.52 - 1.57 (Plagioclase)  
+
1.52 - 1.57 (plagioclase)  
 
|-  
 
|-  
| Birefringence || 0.006 - 0.007 (K-Feldspar)<br />
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| Birefringence || 0.006 - 0.007 (K-feldspar)<br />
0.008 - 0.011 (Plagioclase)
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0.008 - 0.011 (plagioclase)
 
|-  
 
|-  
| Specific gravity || 2.55 - 2,58 (K-Feldspar)<br />
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| Specific gravity || 2.55 - 2,58 (K-feldspar)<br />
2.60 - 2.80 (Plagioclase)
+
2.60 - 2.80 (plagioclase)
 
|-
 
|-
| Lustre || vitreous
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| Lustre || Vitreous
  
 
|}
 
|}

Revision as of 12:29, 23 December 2006

Feldspar
Chemical composition Potassium, sodium and calcium-aluminium silicates

I. K-feldspar (KALSi308)
II . Plagioclase feldspar (isomorphous)

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)

1.52 - 1.57 (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