Traditional clumping cat litter is made up of extremely-absorbent bentonite clay, and although bentonite is usually a natural material, it is not biodegradable and so is just not categorized being a "natural" cat litter. In either case, you would be wise to select a clumping cat litter in a texture https://www.petskyonline.com/search/?query=cats%20best%20litter