Some use materials from pineapple leaves.
the national dress of the filipino male
Most How-to's say to use tool steel and they are not wrong... However, if you need a hammer you can't find on-line or afford, then you might go traditional and forge one out what's in the scrap pile....
Clean silica sand is the main component, with various elements for colouring, or for lowering the melting point of the glass liquid.
plaster.