This vintage sharpening stone, specifically a "HON WELL" brand is made of a synthetic abrasive material like aluminum oxide or silicon carbide, commonly used for quick cutting. It was designed to provide a very fine finishing edge, typically in the range of 4000 to 8000 grit. This Hone stone is used for grinding and honing the edges of steel tools, such as knives or straight razors.

The American Hone Company. They operated primarily out of Olean, New York, before eventually moving their operations to Moravia, Iowa.

While this specific "HON WELL" model doesn't have a singular recorded patent date, these types of synthetic barber hones were most prevalent from the 1920s through the 1940s