Iceland spar
noun
a transparent variety of calcite that is double-refracting and is used as a polarizer.
Origin of Iceland spar
First recorded in 1820–30
British Dictionary definitions for iceland spar
Iceland spar
noun
a pure transparent variety of calcite with double-refracting crystals used in making polarizing microscopes
Scientific definitions for iceland spar
Iceland spar
[ īs′lənd ]
A form of calcite that is transparent and causes light passing through it to refract in two directions (forming a double image of an object seen through it). Iceland spar occurs in perfect rhombohedrons and is used in optical instruments.