Not clay, It's white and a huge bag is around 12 pounds. I talked to the manufacturer and they said that it was safe to use as cat litter. I got two bags yesterday, if it works well I'll let you know. I hope so, it should make the litter boxes so much easier and less stinky and cheaper! It sucks all the moisture up fast, even the poop will dry out and not stink. http://instazorb.com/