Both are minerals, one is metamorhic creation and the other a sedimetary creation . Limestone is made from mollusc and other aquatic life that settles on the ocean floor and gets compressed under weight pushing down on top of it and a mass formation. Zinc or blende as it can be known is a metal that forms and forced up through mass formations along with things like quartz and other minerals. as veins or lodes as they are called and only form a small percentage of the rock structure. Limestone forms on the earths crust, zinc forms in the magma under the crust.
