firestone

fire·stone

F0139300 (fīr′stōn′)n.1. A flint or pyrite used to strike a fire.2. A fire-resistant stone, such as certain sandstones.

(ˈfaɪəˌstəʊn) n (Geological Science) a sandstone that withstands intense heat, esp one used for lining kilns, furnaces, etc

Thesaurus

Noun	1.	firestone - a piece of flint that is struck to light a fireflint - a hard kind of stone; a form of silica more opaque than chalcedony
	2.	firestone - a sandstone that withstands intense heat; used to line fireplaces and furnaces and kilnssandstone - a sedimentary rock consisting of sand consolidated with some cement (clay or quartz etc.)