Iceland spar

noun

1. a transparent variety of calcite that is double-refracting and is used as a polarizer.

Iceland spar

noun

1. a pure transparent variety of calcite with double-refracting crystals used in making polarizing microscopes

Iceland spar

/ īs′lənd /

1. 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.

Word History and Origins

Origin of Iceland spar¹

First recorded in 1820–30

Example Sentences

Calcite when pure, as in the well-known Iceland-spar, is perfectly transparent and colourless.

From Project Gutenberg