41. They consist essentially of feldspar with hornblende ( generally of brown color ) and pale pyroxene . 42. Phenocrysts are dominated by plagioclase; in the latter stages of activity biotite dominates over pyroxene . 43. The pyroxene is, yellow or green, and is surrounded by formless areas of nepheline. 44. Feldspar, amphiboles, pyroxenes , and volcanic glass are the principle donors of clay minerals. 45. Pyroxene andesite is the dominant component.46. In meteorites it occurs with perovskite, melilite, hibonite, spinel and calcium rich pyroxene . 47. The tholeiite contains plagioclase and pyroxene . 48. Thin section analysis revealed that the crystals are mostly plagioclase, with some pyroxene and olivine. 49. They contain hornblende and pyroxene with a total content of 58-61 % of SiO 2. 50. The first minerals to form in this ocean were the iron and magnesium silicates olivine and pyroxene .
