Before humans figured out to make tools from metal, they made stone tools. Obsidian could be made into sharp and effective blades and arrowheads.
Why It Matters
- In North America, obsidian is found in some volcanic regions of the West.
- Obsidian comes from molten magma that cools quickly. It contains no crystals. (Obsidian is not a liquid; it is a non-crystalline solid.)
- The composition of obsidian is about 70% silica so it is glassy and hard.
- Obsidian is so viscous that it often forms domes.
- Obsidian breaks with conchoidal fracture, smooth and curved.
- The edges of the stone can be really sharp. This is beneficial for stone tools.
With the links below, learn more about obsidian tools. Then answer the following questions.
- Living History School, How to make an obsidian arrowhead with a deer antler: http://www.youtube.com/watch?v=tWp5TVCFTxo
- OHCEditor, Obsidian Blades: http://www.youtube.com/watch?v=ZjDOqjbCXe4
- How do you get a chip of obsidian from a rock?
- What is the technique for pressure flaking?
- Why would ancient people go to the effort of getting rock to make tools from 1800 miles away?
- Were the obsidian blades made at Yellowstone where the rock was found or at Hopewell Mountain where the blades were used? What is the evidence?
- What do you think the enormous blades might have been used for?
- Why is obsidian a rock but not a mineral?