Lignite dry strength which helps in preventing moulds from breaking or cracking during the pouring or cooling processs in the foundry industry.Lignite.
White clay in rough cube shapes of about 30 cm. As the corners were knocked through handling and storage these cubes became rounded and ball shaped. It also is sometimes referred to as plastic clay.
Quartz silica sand of a millimeter to two millimeters in diameter, falling between silt and gravel in the spectrum of sizes. There are many varieties of sand in the world, each with their own unique composition and qualities.
Calcium bentonite powder two varieties of bentonite are available - sodium bentonite (high swelling, gelling and thermal durability) and calcium bentonite (more commonly available worldwide but with less swelling).