Painted designs are an early development, some remarkably fine work made before 3000 bce coming from excavations at Ur and elsewhere in Mesopotamia, as well as urns from Banshan in Gansu that date back to 2000 bce. The earliest pottery colours appear to have been achieved by using slips stained with various metallic oxides (see above Slip decorating). At first these were undoubtedly oxides that occurred naturally in the clay; later they were added from other sources. Until the 19th century, when pottery colours began to be manufactured on an industrial scale, the oxides commonly used were those of tin, ...(100 of 42409 words)