The aluminum industry could shift from using bauxite to using anorthosite and clay. Labradorite is the principal component of the igneous rock type anorthosite. It comprises various rock types including gabbro, ferro diorite, anorthosite and granophyre. One is a mafic unit with gabbro, norite, amphibolite and anorthosite. Rapakivi granites are often found associated with intrusions of anorthosite, norite, charnockite and mangerite. The composition consists predominantly of cumulate rocks, including leuconorite, anorthosite, chromitite, and melanorite. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro. Anorthosite, quartz and feldspar constitute the principal rocks. It is also found in metamorphosed anorthosite complexes. Here it can form anorthosite layers. The co-crystallizing plagioclase crystals float, and eventually are emplaced into the crust as anorthosite plutons. Archean anorthosites are distinct texturally and mineralogically from Proterozoic anorthosite bodies. The primary economic value of anorthosite bodies is the titanium-bearing oxide ilmenite. In geological terms, black granite might be gabbro, diabase, basalt, diorite, norite, or anorthosite. There are also charnockite and anorthosite intrusions that intersect metasediments and orthogneiss.