Earthstone Clay ES 40 Handbuilding 100 KgEarthstone Clay ES 40 Handbuilding Available in 25 Kgs bags. Minimum order 100 Kgs. ES 40s appearance and firing range are similar to Earthstone Original (ES 5). ES 40 is a high quality white clay body; the addition of coarse molochite makes it an incredibly strong clay. It is heavily enough grogged to make the most extreme sculptural forms and is highly resistant to warping and cracking. This makes it suitable for handmade tiles and ceramic murals.