Abstract
Cobalt-rich spinel is found as a ~200 μm inclusion, together with a glassy phase, in a gem-quality blue sapphire from Bo Ploi, Thailand. Its composition is directly analogous with that of cochromite, a previously reported rare cobalt-rich chromite. Transition elements decrease in abundance from core to rim of the spinel while the other elements increase. Crystal chemical considerations suggest that a vacancy-creating substitution mechanism may be operative in the cobalt-rich spinel. The glassy phase coexisting with the spinel is likely to be the product of heating by the host basaltic magma. -from Authors
Original language | English |
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Pages (from-to) | 247-258 |
Number of pages | 12 |
Journal | Mineralogical Magazine |
Volume | 58 |
Issue number | 2 |
Publication status | Published - 1994 |