A mixture of open semitransparent patches of water and broken pack ice. The ice has some ambient response to simulate unnatural bluish glow of ice (level set to respond correctly to full white ambient if required). Transparency may be dispenced with if necessary to speed up render times. Some care will have to be taken to select the correct viewing scale. Due to the complexity of the material, it is quite slow to render and AA is definately needed to apprecaite the correct effect.