| 1. | In slowly cooled intrusive igneous rocks, pigeonite is rarely preserved.
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| 2. | At lower temperatures, pigeonite is unstable relative to augite plus orthopyroxene.
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| 3. | Quartz is absent, as are orthopyroxene and pigeonite.
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| 4. | Pigeonite is a mineral in the Clinopyroxene group.
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| 5. | Olivine may also be a phenocryst, and when present, may have rims of pigeonite.
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| 6. | Pigeonite can be seen in the lower portion of the Mg-Fe-Ca Pyroxene quadralateral.
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| 7. | It was discovered in 1982 during the chemical analysis of The North Haig olivine pigeonite achondrite ( ureilite ).
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| 8. | Pigeonite crystallizes in the monoclinic system, as does augite, and a miscibility gap exists between the two minerals.
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| 9. | Pigeonite is found as phenocrysts in volcanic rocks on Earth and as crystals in meteorites from Mars and the Moon.
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| 10. | In tholeiitic basalt, pyroxene ( augite and orthopyroxene or pigeonite ) and calcium-rich plagioclase are common phenocryst minerals.
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