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Five varieties of pyrochlore have been identified at Oka.
1. A metamict variety containing uranium and thorium; bright red color, fine-grained, associated with ijolitic rocks. a0 = 10.43 ± 0.05 A.
2. A certain variety; chocolate-brown, coarse-grained, euhedral (octahedra and dodecahedra), associated soda pyroxene marble. G = 4.38, a0 = 10.393 ± .001 A.
3. A thorian variety; brownish red, in calcite-forsterite rock. a0 = 10.428 ± .005 A.
4. A zirconian variety; reddish brown to black, occurrence in carbonatite. a0 = 10.395 ± .001 A.
5. A fifth variety is known to be high in Nb2O5; the complete chemical composition is not available but the Nb2O5 content is greater than 60%.
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