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Obertiite Mineral Data
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General Obertiite Information
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 Chemical Formula: |
NaNa2(Mg3Fe+++Ti)Si8O22(O,F,OH)2 |
| Composition: |
Molecular Weight = 855.28 gm |
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Sodium 8.06 % Na 10.87 % Na2O |
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Magnesium 8.53 % Mg 14.14 % MgO |
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Titanium 5.60 % Ti 9.34 % TiO2 |
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Iron 6.53 % Fe 9.34 % Fe2O3 |
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Silicon 26.27 % Si 56.20 % SiO2 |
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Hydrogen 0.03 % H 0.26 % H2O |
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Oxygen 44.43 % O |
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Fluorine 0.56 % F 0.56 % F |
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- %
F -0.23 % -O=F2 |
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______ ______ |
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100.00 % 100.47 % = TOTAL OXIDE |
| Empirical Formula: |
Na3Mg3Fe3+Ti(Si8O22)O1.5F0.25(OH)0.25 |
| Environment: |
In cavities with basaltic flows. A member of the anhydrous amphibole group. |
| IMA Status: |
Approved IMA 1998 (Dana # Added) |
| Locality: |
The Bellerberg quarry, Laacher See district, Eifel region, Germany. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Dr. Roberta Oberti (1951-), Pavia, Italy, for her contributions to the understanding of the crystal chemistry of the amphibole group. |
| Synonym: |
Ferric-nyboite |
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IMA1998-046 |
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