Knife blades are made from a variety of materials, including metal, titanium, plastic, ceramic, glass and obsidian. Obsidian is produced in nature when felsic lava is forced from a volcano and does not experience crystal growth while cooling. Because of its chemical composition, which allows it to obtain a nearly molecular thinness, it is an idea material for making surgical scalpel blades. It is a naturally formed glass that can be crafted to a much sharper cutting edge than steel scalpels. The material is also used in some sports knives.

Step 1

Stand in front of the kitchen counter and place the sharpening stone, vertically, on the counter top.

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Step 2

Place the blade flat on the stone, positioning the length of the knife at a 45-degree angle to the stone.

Step 3

Grasp the handle of the knife, with your index finger along the blade's backside.

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Step 4

Raise the blade's flat side surface off of the stone at a 20-degree angle, but keep the blade edge on the stone.

Step 5

Draw the knife toward you, while keeping the edge in contact with the stone. While doing so, maintain the 20-degree angle achieved when lifting the backside of the knife from the stone and the 45-degree angle of the knife's length position to the stone. Apply medium pressure as you draw the knife across the stone.

Step 6

Turn over and repeat the procedure on the other side of the blade while maintaining the position of the angles.