A glass object can be decorated by scratching a design into it with a hard, pointed object. In the 17th century this was done with a diamond stylus. Any design can be created by this technique - a pattern, a landscape, human figures or lettering - but there is a significant risk that the glass will break. From the 18th century onwards, the designs were usually engraved by holding the piece against a fast-turning wheel. Far less detail can be achieved this way but large surfaces can be ground.
The process of cutting into the surface of an annealed glass object either by holding it against a rotating copper wheel fed with an abrasive or by scratching it, usually with a diamond.
