1. Plural of firestone; a hard stone that produces sparks when struck with steel, historically used to start fires.
Usage: archaic; historical
2. A type of stone or mineral that is resistant to heat and used in furnaces, kilns, or fireplaces.
Usage: technical; construction

Examples

• Early settlers carried firestones in their packs to kindle fires in the wilderness.
• The blacksmith struck his firestones together to create sparks for the forge.
• Firestones were essential tools before the invention of modern matches.
• The furnace was lined with firestones to withstand extreme temperatures.
• Archaeologists discovered ancient firestones at the prehistoric campsite.