Fossilized Cobblestone.

If you combine a buck of water with any fish (Besides axolotl) and add lava, they will create the new fossilized cobblestone. Using the new brush you can excavate the new block and find the fishes fossil. But be careful! If you got to fast it will break! Once you get the fishes fossil you can either keep this as a trophy or you can exchange it to a fisherman villager for some emeralds! The difference between cobblestone and fossilized cobblestone? Well lets say unlike normal cobblestone Fossilized cobblestone actually erodes in the rain. Fossilized cobblestone recreated in survival will have a lower chance of obtaining a fossil then those that are naturally generated