Cobalt Carbonate (CoCO3) is a powerful colourant and flux; insoluble in water.  The powder is very fine and easily dispersed through the glaze.  Melts at low‐fire temperatures.  Cobalt Carbonate is slightly weaker than Cobalt Oxide, but disperses better.  Gives strong blue colours, transparent if dilute.  Ultramarine with alkaline fluxes; Purple with Manganese; Green with Titanium.  Screen glazes containing Cobalt Carbonate well to avoid spotting.