A method of polishing to reduce surface roughness of at least one surface of a glass ceramic substrate that includes an amorphous glass portion and a crystalline portion. The method comprises at least one step of polishing the surface using a polishing pad and an abrasive polishing slurry. The polishing slurry comprises a first concentration of Ceria particulates and a second concentration of Silica particulates. The amorphous glass portion and the crystalline portion of the at least one surface are polished substantially equally.