These are little colorful balls of calcium suppliment marketed for hamsters. They are made with crushed shells, limestone, tapioca(for binding) and food color. Supposedly fruit flavoring added too. My crabs love these. Dip one in water, and leave it alone in the tank for a few hours so it won't be rock solid- but even in it's solid form they start picking at it and soaking it themselves. They keep trying to steal them & bring them back under the subsrate with them.