FELDSPATHOIDS Antonyms

• rare plagioclastic feldspar occurring in many igneous rocks

• plutonic igneous rock having visibly crystalline texture; generally composed of feldspar and mica and quartz

• something having the quality of granite (unyielding firmness)

• a transparent or translucent gemstone with a pearly luster; some specimens are orthoclase feldspar and others are plagioclase feldspar

• a white or colored monoclinic feldspar

• any of a series of triclinic feldspars that form rocks

• colorless glass made of almost pure silica

• a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities

• A common feldspar of igneous, plutonic, and metamorphic rocks, made of potassium aluminum silicate, with the chemical formula KAlSi3O8.