In ceramics, bodies of different colours can be kneaded together to produce a marble-like result. But caution is needed.
The practice of mixing bodies of two or more different colors (often porcelains colored using metal oxides or stains). It is important to consult the stain manufacturer's website to see which stains they recommend for bodies. Experimentation is needed with each color to determine optimal percentages (these vary widely, usually 5-20%). Vitreous porcelains will produce brighter colours.
To produce a quality fired product it is important that the bodies have as-similar-as-possible fired shrinkages, otherwise stresses accumulate within and seek opportunity for release, making pieces into time-bombs! They must also have as-similar-as-possible thermal expansions, otherwise rapid temperature changes will suddenly build stresses that can produce spectacular failures).
Cone 6 translucent marbled bowl by Tony Hansen
A transparent glazed. It is a made from Plainsman Polar Ice in 2014 (a New Zealand kaolin based porcelain) and fired to cone 6 with G2926B clear glaze. 5% Mason 6306 teal blue stain was added to the clay, then this was wedged only a few times. The piece was thrown, then trimmed on the outside at the leather hard stage and sanded on the inside when dry.
Cone 6 porcelain marbled and thrown
These bowls were made by Tony Hansen using a mixture of white and stained New-Zealand-kaolin-based porcelain (Plainsman Polar Ice) fired at cone 6. The body is not only white, but very translucent.
Marbled cone 6 clays with rutile blue glaze
These are Plainsman M340 buff stoneware and Plainsman Coffee black wedged together. The glaze is Alberta Slip GA6E.