Flint knapping is a technique almost as old as humans. Flint can be heated and then struck to break off the edges to make many tools. They have been made into hide scrapers, knives and arrowheads, among others If you aren't familiar, go read Valley of the Horses by Jean Auel. It is my favorite of her series about early humans. It starts with Clan of the Cave Bear. You can read about the history and techniques here, if you are interested.
One of our recent guests is an avid flint knapper. He makes many objects, but he particularly likes the challenge of making arrowhead earrings. It is very difficult to make two mostly identical arrowheads out of stone. It may break a different way or the stones may not match in color or many other obstacles.
I showed these guests some of my baskets that I make and we decided to work out a trade. Ray sat down outside with a deer hide on his lap and Julie and I went up to my workroom. She picked out the fabrics she liked and we decided on a shape. We each began the process of making a unique piece of art.
This is the basket I came up with. I left the embellishment off as we had decided that Ray wanted to wire wrap an arrowhead to attach to the basket and he didn't have any wire with him.
This is the arrowhead that I received in exchange.
Barter is also as old as humans, so I liked the whole concept.