calc-spar

[ kalk-spahr ]

/ ˈkælkˌspɑr /

calcite.

Origin of calc-spar

1815–25; < Swedish kalkspat calc-spar; t > r by association with spar³; see calc-

It is harder than gypsum, but not so hard as calc-spar; flexible and elastic; spec.

A Dictionary of Arts, Manufactures and Mines |Andrew Ure
It is considered by Dr. Feussner to be the most perfect prism capable of being prepared from calc-spar.

Scientific American Supplement, No. 441, June 14, 1884. |Various
Its beds are from one to two feet thick, and much intersected by small veins of calc-spar.

Narrative of a Second Expedition to the Shores of the Polar Sea |John Franklin
Calc-spar will not supply the place of flint, nor lead the place of steel, in the production of fire by collision.

Fragments of science, V. 1-2 |John Tyndall

In calc-spar, as just stated, the ordinary ray is the most refracted.

Six Lectures on Light |John Tyndall