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Plagioclase Mineral Data
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General Plagioclase Information
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 Chemical Formula: |
(Na,Ca)(Si,Al)4O8 |
| Composition: |
Molecular Weight = 270.77 gm |
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Sodium 4.25 % Na 5.72 % Na2O |
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Calcium 7.40 % Ca 10.36 % CaO |
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Aluminum 9.96 % Al 18.83 % Al2O3 |
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Silicon 31.12 % Si 66.57 % SiO2 |
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Oxygen 47.27 % O |
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______ ______ |
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100.00 % 101.48 % = TOTAL OXIDE |
| Empirical Formula: |
Na0.5Ca0.5Si3AlO8 |
| Environment: |
Igneous and metamorphic rocks. Group name for Na, Ca feldspars. |
| IMA Status: |
Not Approved IMA |
| Locality: |
Common world wide occurrences. Link to MinDat.org Location Data. |
| Name Origin: |
From the Greek plagios - "oblique" and klao - "I cleave" in allusion to the obtuse cleavage angles of the good cleavages. |
| Name Pronunciation: |
Plagioclase + Pronunciation  |
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