A very hard, fine-grained quartz that sparks when struck

• Nodules in chalk or limestone, used for tools and fire

A shaped piece of flint used to strike sparks

• A gunflint for flintlock firearms or a firestarter chip

A small spark-producing cylinder in a cigarette lighter

• Often a synthetic alloy rather than true flint

A variety of corn with a very hard outer hull

Something extremely hard

• A character or manner that is cold or unyielding

To face, pave, or decorate with flint