 This process caused the fabric of the clay to change color from its natural red to black.Thus, in contrast to the black-glazed Campanian ware of the Greek colonists in southern Italy, the lustrous, shiny, black surface of many bucchero pots was achieved by diligent burnishing (polishing) or, occasionally, through the application of a thin slip (clay emulsion).The term "Bucchero" derives from the Portuguese word "búcaro", meaning "odorous clay", because this type of pottery was reputed to emit a special odor.