simple past tense and past participle of spar

(rail transport, UK) Initialism of signal passed at red.

A transparent form of calcite, used to demonstrate the polarisation of light.

(mineralogy) A massive variety of fluorspar, found in Derbyshire, England, and wrought into vases and other ornamental work.

dolomite

Alternative form of sparrow hawk

(mineralogy) wollastonite

(mineralogy) An altered variety of enstatite, exhibiting, in certain positions, a bronze-like luster.

aragonite

(mineralogy) A ferruginous variety of dolomite, in part identical with ankerite.