Metallic materials applied on glazed surfaces. Lusters are pure metals dissolved by hydrochloric acid, which are then suspended in an oil base that can be applied with a brush. Precious metals are often used but whatever the metal, lusters are generally only used as highlights such as pinstripes or small applications. The firing is at an extremely ... Found on https://www.lakesidepottery.com/HTML%20Text/Tips/A%20pottery%20glossary.htm