plagioclase


plagioclase

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.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on plagioclase, visit Britannica.com.

Seen & Heard

What made you look up plagioclase? Please tell us what you were reading, watching or discussing that led you here.