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How to Chip Obsidian

Obsidian is an igneous rock that forms from volcanic magma. When the magma escapes from an erupting volcano, some of the material cools extremely fast, forming obsidian. Because of the rapid cooling, obsidian looks like black glass. When obsidian breaks, it forms a conchoidal fracture, which has a swirl pattern and thin, sharp edges. Obsidian is a popular rock because you can chip the material to form arrowheads, primitive tools and accessories such as jewelry.

Things You'll Need

Chalk
Hammer
Chisel
Towel

Instructions

- 1
  Mark your obsidian with the chalk outlining the areas that you want to chip. You can chip the rock into a particular shape, like an arrowhead, or you can make many small pieces for jewelry or other accessories.
- 2
  Place the chisel tip on the area where you want to begin to chip the rock.
- 3
  Strike the chisel with the hammer gently. If the rock does not break, hit the chisel again with increasing strength until the rock breaks. Continue this process until you create all of the chips that you want or until you create the ideal shape.
- 4
  Wipe the obsidian chips with a towel to remove the chalk and give the rock pieces a polish.

Rocks & Minerals