Feldspath n. : A name given to a group of minerals, closely related in crystalline form, and all silicates of alumina with either potash, soda, lime, or, in one case, baryta. They occur in crystals and crystalline masses, vitreous in luster, and breaking rather easily in two directions at right angles to each other, or nearly so. The colors are usually white or nearly white, flesh-red, bluish, or greenish.

Example:


Taxonomy
Feldspar, plagioclase feldspars, alkali feldspar, Compositions, albite, Mineral, anorthite, potassium feldspar, textures, Rock, Solid solutions, free encyclopedia, endmember, barium, Amethyst Galleries, Perthite, plagioclase, monoclinic.

Defination from the web:
Feldspath) Jump to: navigation, search. This article is about a mineral. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). Collected by Apollo 16 from the Lunar Highlands near Descartes Crater. ...