Used in manufacture of some porcelains. Orthoclase is the common feldspar found in felsic silicate rocks. Striations common on cleavage planes. Luster generally vitreous to pearly. Used in manufacture of some ceramics.
Plagioclase is the common feldspar found in intermediate to mafic silicate rocks.
No cleavage, but some samples may exhibit parting. Luster generally vitreous. Mined for refractory sand used in casting industry. A common ferromagnesian mineral in mafic to ultramafic silicate rocks. 7.0 Conchoidal fracture Colorless or white when pure, but may be any color 2.6 As crystals with hexagonal cross section, often with striations on prism faces.