500g COPPER CARBONATE

CuCO3·Cu(OH)2  A source of copper oxide (CuO) and a recipe substitute for the same by adding 40% more. 3% added to most glazes produces a clear green. In alkaline glazes the colour shifts to turquoise blue.  At 7% or more, metallic surfaces develop. Fired in a reduction atmosphere, red colours are achieved with ½% or less.

Note: Glazes become increasingly susceptible to food acid attack as copper oxide levels increase.

For more information on copper carbonate, see the Digitalfire.com Reference Library  of ceramic materials.