What is a flint knife made of?

A flint knife is made of flint, a type of sedimentary rock that is composed primarily of microcrystalline quartz. Flint is a hard, brittle material that breaks into sharp edges when chipped, making it ideal for making knives and other tools. Flint knives were used by humans as early as the Stone Age, and they continued to be used until the Bronze Age when metal knives became more common.