Using bleach and water to shine pebbles
I've collected rocks and tumble polished rocks. It is not possible that just sitting in bleach water tumble polished the stones. You can leave the stones in bleach water till you die and they still won't get polished. The only explanation is that you bought polished stones and put them into the bleach water. Over a period of time you just forgot what type of stones that you started with. 

The other point is that "river rocks" (rocks smoothed in a river...) will look much smoother when wet because the water wets the surface and "hides" some of the surface roughness. So dry Petoskey Stones just look sort of mottled gray stones, but when wet the coral pattern shows nicely.