Copper Carbonate [CuCO•CU(OH)2] is a bluish-green powder.
This chemical is used as a blue coloring agent in pyrotechnics.
Although they are not interchangeable with copper carbonate, other blue coloring agents are copper (II) oxide, copper (II) oxychloride and copper benzoate.
Fireworks formulas using Copper Carbonate:
Blue Steel Gerbs
Blue Go Getters
Formulas: Shimizu 216 Blue & Blue Pill Box Star, Lancaster pg. 92 & Bruce Snowden Blue Star, Pyrotechnica I
Morning Glory Blue
Blue Star from D. Haarmann's "Pyrotechnic Formulary"