Things You'll Need
Fingerless leather gloves
Large leather pad
Hammer stones of varying sizes
Wood or antler handle
The art of flintknapping, crafting blades out of stones, dates back thousands of years and has been practiced by cultures around the world. The key to producing a quality obsidian knife is the quality of the stone. Obsidian is a volcanic rock, often called volcanic glass, which varies in color, but is commonly grey or black and is composed mainly of silicon dioxide. Obsidian knives are capable of cutting, but are mainly used as decorative artifacts. The handles are traditionally fashioned out of antlers or wood. A working knowledge of flintknapping is crucial for this craft.
Sit in a comfortable position. Don your fingerless leather gloves and protective eyewear and cover your lap with a large pad made out of leather. Hold the obsidian in your fist.
Locate the center line on the obsidian. The center line is the imaginary center plane of your rock. You will only be hitting your rock below this line.
Prepare the area you wish to remove, the platform, by abrading it with a hammer stone; Quartz, sandstone and pumice make excellent abraders. Good platforms are located below the center line and are isolated from the rest of the rock, meaning that material on either side is abraded away giving you a small protrusion as a target for your billet.
Shape your blade. Using your billet, apply short, direct hits to the abraded surface to remove flakes of obsidian until the blade is the desired shape. You can abrade the edges to dull the blade or employ various knife sharpening techniques to sharpen it when the knife is completed.
Cut a notch the size of the base end of the obsidian in the top end of your handle with a small saw. Apply epoxy resin.
Insert the obsidian into the notch and secure with sinew.
If you do not possess flintknapping skills, you can purchase an obsidian blade from numerous online retailers.
If you prefer to avoid using epoxy resin, natural glues include pine pitch and hide glue.
If you carve the handle after the blade is attached, wrap the blade in thick cloth to avoid injury.
Placing the obsidian on a flat surface will likely result in breakage, while holding it in your fist absorbs the shock and vibrations produced by the billet blows.
The process of shaping gets trickier as the obsidian thins; it may take multiple rocks before you are able to produce a working blade.