Tourmaline (dravite) from the Boehls Butte anorthosite, Idaho, U.S.A.
Tourmaline (dravite) from a layered two-plagioclase anorthosite in the Boehls Butte quadrangle, Idaho, has the following structural formula: (Na0.55Ca0.17)0.72(Mg1.96Fe0.57Mn0.01Ti0.04V0.03Al0.47)3.08Al6(BO3)3.02Si5.98O18(OH,F)3.35. The indices of refraction are ω = 1.647(1) and ε = 1.621(1), and th...
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| Format: | Article |
| Language: | English |
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Geological Society of Finland
1987-12-01
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| Series: | Bulletin of the Geological Society of Finland |
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| Online Access: | http://www.geologinenseura.fi/bulletin/Volume59/sgs_bt_059_2pages_091_095.pdf |