Very large bonfires might reach about 2000F. Sand melts to glass at 3000F.
Obsidian is volcanic glass. We might have also seen glass near meteorite impacts, or perhaps lightning strikes. If not from those natural phenomena, we might have discovered it as a side product of smelting copper, or perhaps some shop's apprentice messing around with the furnace.
Obsidian is volcanic glass. We might have also seen glass near meteorite impacts, or perhaps lightning strikes. If not from those natural phenomena, we might have discovered it as a side product of smelting copper, or perhaps some shop's apprentice messing around with the furnace.