Stone Type: Glass
Glass is created by fusing molten sand with soda and lime and cooling it rapidly. It is amorphous in structure, contains about 70-75% silica, and is ideal for flaking. Obsidian is a naturally-occuring glass erupted by volcanoes, and industrial smelting furnaces can produce glass as a byproduct. First Nations people sometimes used glass as a substitute for stone in the recent past.