There is also a small amount of hematite, pyroxene and sericite.
The lava is black, rich in pyroxene, and strongly attracted by a magnet.
pyroxene is the usual ferromagnesian mineral, and resembles that of the tephrites and basanites.
The pyroxene is morphic, yellow or green, and is surrounded by formless areas of nepheline.
Their pyroxene is principally aegirine or aegirine augite; some of them are rich in melanite.
Diopside, dī-op′sid, n. a grayish and readily cleavable variety of pyroxene.
Both are common alteration products of magnesian silicate minerals such as olivine, pyroxene, and amphibole.
Jeffersonite, jef′er-son-īt, n. a greenish-black variety of pyroxene.
Omphacite, om′fa-sīt, n. a grass-green granular variety of pyroxene, one of the constituents of eclogite.
The rock was of garnet gneiss, traversed by black dykes of pyroxene granulite.
Any of a series of dark silicate minerals having the general chemical formula ABSi2O6, where A is either calcium (Ca), sodium (Na), magnesium (Mg), or iron (Fe), and B is either magnesium, iron, chromium (Cr), manganese (Mn), or aluminum (Al). Pyroxenes vary in color from white to dark green or black and are characterized by a rectangular-shaped cross section. They can be either monoclinic or orthorhombic and occur in igneous and metamorphic rocks. The minerals enstatite, diopside, and augite are pyroxenes.