The crystalline glaze is one of the most challenging effects that the studio potter can strive to perfect. The spectacular appearance is due to crystals that form within the glaze during firing.

Like frost growing on a cold window pane, the crystals are formed at random, but unlike ice, they are created when the intense heat of the kiln transforms the initially dull glaze into a sparkling array of brilliant shapes and colours – a process which mirrors the formation of minerals within the Earth's mantle.

The crystals are three dimensional and as light catches them they shimmer like holograms.

Richard Bideau has been developing his own crystalline glazes for fifteen years and now uses them on a range of finely thrown porcelain forms.