Koh-i-noor Keraplast Air Drying Clay is soft and easy to use. Just spray or mix it with water to keep it moist and pliable. Mold it, sculpt it or use modeling tools to add details. When done, expose it to air and it will harden - no need to fire in a kiln. You can paint over it using any acrylic paint. Available in White or Terracota.
I bought the keraplast a few months ago i used it for my small scale sculptures and combined it to some of my animation characters, it dries well and perfectly workable, it doesnt need firing. Very good product.