These clear glazed porcelain mugs are fired at cone 6. The one on the right has 0.2% Mason 6336 stain added to to G2926B base glaze. It matters which stain, some agglomerate and causes specking, this one disperses well.
Standard porcelains used by potters and for the production of sanitary and table ware have surprisingly similar recipes. But their plasticities vary widely.