Although materials like horn, stone and teflon are being used to make them, the classic bone folder is a shaped piece of bone carved from real animal bones, often deer or elk. Bone is an ideal material to use for smoothing, scoring, and creasing paper and cloth because it is sturdy, smooth and grainless. It can also be used for burnishing (polishing and imparting glossiness) and with sufficient (or excessive) pressure its edge is sharp enough to cut paper or cloth.
Many bone folders are carved with ornate handles or other decorative features, but a basic bone folder is typically shaped like a wooden tongue depressor or a large popsicle stick with rounded ends or a pointed end for working in corners.
Basic bone folders can usually be found in hobby and craft stores and online bookbinding supply merchants. More ornate bone folders are harder to find but there is nothing to prevent the owner of a plain bone folder from personalizing it with a little carving of their own.
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