flinty

The fact that she comes from flinty, northern coal-miner stock.

So saying, he took a piece of flinty stone, and struck it hard against another, till they gave red sparks between them.

Dawson added the last because of the flinty look that had suddenly leaped into Farmer's eyes.

Dear John,—Dost expect to elicit a spark from so dull a steel as myself, by that flinty subject of thine?

The certain approach of death had already humanised and softened his flinty heart.

The sled runners squeaked loudly in the flinty snow, and Connie halted the dogs and surveyed the forbidding landscape.