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