Stone Type: Manufactured materials
Human-produced materials are sometimes sufficiently siliceous to flake into tools. Examples include glass and highly-fired stoneware ceramics. Smelted metals such as copper and bronze—and, more recently, iron—were used to flake stone, and glassy metallurgical slags are often suitable for flaking. Most modern hobbyist flintknappers prefer to use copper tools for both percussion and pressure flaking.