Use a wire to cut each of the balls into quarters and then swap two quarters, so each ball has two white clay quarters and two dark clay quarters (they'll look a little like juggling balls). The balls are then ready to throw and will give a great marble effect.

How do you do Neriage?

Neriage, or agateware, is done by laminating different colored clays together and throwing them on a wheel to develop a swirling and spiraling blend of the clays. Objects made this way can be left with the swirl pattern, or altered by various forms of cutting the surface, with fluting and faceting.

What is agateware pottery?

Agateware, in pottery, 18th-century ware of varicoloured clay, with an overall marbled effect. It was sometimes called solid agate to distinguish it from ware with surface marbling. ... The random mingling of coloured clays, such as red and buff, gave a broad veining to domestic and ornamental pieces.