Greenium is a fictional substance and does not exist in reality. However, if we assume that Greenium is similar to other compounds, its solubility in water would depend on its chemical structure. Some compounds dissolve in water, while others may not.
Copper carbonate reacts with acid to form copper II ions which are blue-green in color. When these copper ions are mixed with hydroxide ions they form copper hydroxide which is then oxidized to form green copper oxide. This green pigment mixed with other materials becomes "greenium."