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.
Stand in front of the kitchen counter and place the sharpening stone, vertically, on the counter top.
Place the blade flat on the stone, positioning the length of the knife at a 45-degree angle to the stone.
Grasp the handle of the knife, with your index finger along the blade's backside.
Raise the blade's flat side surface off of the stone at a 20-degree angle, but keep the blade edge on the stone.
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.
Turn over and repeat the procedure on the other side of the blade while maintaining the position of the angles.