The Pearl Oyster is a block added by Mariculture. Pearl Oysters are found on the bottom of the sea floor in the overworld. Pearl Oysters will slowly produce Pearls if provided the correct conditions. The Oyster must be fed with sand and kept underwater. To feed an Oyster simply right click it with a block of sand in your hand, then it will begin producing a Pearl. Once the Pearl is visible and the process is complete, just right click the oyster to retrieve it. The most common and easy method of harvesting an Oyster is by breaking the block underneath it.
You can change an Oysters Pearl color by placing the corresponding Pearl Block underneath the Oyster.
Pearl Oysters can also be used to make Beef and Oyster Pies.