The coefficient of friction, or COF, for Leathered Brazils Julia Soapstone tiles would need to be tested in a laboratory setting using specialized equipment designed to measure COF. This value is specific to the surface texture and condition of the tiles, and can vary depending on factors such as the finish, roughness, and moisture content.

It is recommended to consult with the manufacturer or supplier of the tiles for information regarding the coefficient of friction. They may have conducted tests or provide specifications that can help determine the COF of the specific product.