Flint
When flintstones are broken, they have a sharp edge which could be used as a knife, or a scraper.  When flint and an iron-containing material such as pyrite or steel are hit together, they can make a spark. For many centuries, flint was one of the main ways for people in many countries to make fire. People would carry a little box called a "tinder box" which had some tinder along with flint and pyrite or steel. The tinder was used to catch the spark and start a fire. Tinder could be sawdust, cloth, grass or bark. Flints were later used to make a spark to fire a gun. A gun that used flint was called a "flintlock" gun.