View your list of saved words. (You can log in using Facebook.)
About Our Definitions: All forms of a word (noun, verb, etc.) are now displayed on one page.
noun\ˈplā-j(ē-)ə-ˌklās, ˈpla-, -ˌklāz\
Definition of PLAGIOCLASE
: a triclinic feldspar; especially: one having calcium or sodium in its composition
Origin of PLAGIOCLASE
Greek plagios oblique + klasis breaking, from klan to break — more at clast
First Known Use: circa 1868
Any member of the series of abundant feldspar minerals that usually occur as light- to medium-grey-coloured, transparent to translucent grains or crystals. Plagioclase ranges in composition from albite to anorthite. It is used in the manufacture of glass and ceramics; iridescent varieties are valued as gemstones. The primary importance of plagioclase, however, derives from its role as a rock-forming mineral.