Why is calcium carbonate relatively insoluble in water?
Simply because the electrostatic bonds between the carbonate anion and the calcium ion are too strong to be overcome by solvation by water molecules.
In fact most carbonates are insoluble in water (the exceptions are?). Carbonate is a doubly charged negative ion that should form strong electrostatic bonds with metal ions - the doubly charged calcium ion,
As physical scientists, however, we seek actual data, and I confess that I cannot find an appropriate table. I did find