Clay is a substance that is used to make a variety of different products. One of the most common uses of clay is to create dinnerware and decorative objects. The use of clay to create pottery dates back to 3000 BC and many clay articles have been found in archeological sites the world over. Its ability to harden when dried has made it a valuable material for making pots, plates, cups and other useful containers.
What Is Clay And Where Does It Come From?
Clay is a naturally occurring mineral found on the earth’s crust. It has natural plasticity and can be harden when dried or fired. It is found all over the world below the top soil and is usually dug up from the ground. Clay is formed when igneous rock is broken down into tiny particles. The rock usually contains silicate which is derived from silicic acid. Clay is constantly being formed by the weathering (movement of water and mineral acids through rock surfaces) of rock found in the earth crust. Clay can be either dry or moist depending on whether water runs through the area. Large deposits of clay are often found in areas which contained water such as river and lake beds or marine areas. Large deposits can also be found on mountain sides or low lying area where water is constantly present. Clay however is found anywhere below the immediate surface of the earth but is often in its dry state. This dry clay can be mixed with water to create the moist clay substance used to create pottery.
Types of Clay
Clay is used to create such products as ceramics and porcelain. It comes in three different classes earthenware, mid-fire stoneware and high-fire stoneware. Earthenware clays are the most commonly used and can be sticky in consistency. They have high plasticity meaning that they can be worked easily. When moist, earthenware clay comes in colors such as red, yellow, orange and light gray. Stoneware clays are usually grey in color and again have good plasticity. They also tend to be less sticky than earthenware clays. High quality Kaolin clays which are used to make porcelain are usually light gray in color when wet and fired to an almost white or pure white color. This type of clay has less plasticity than other clays due to its high mineral purity and can be difficult to work with.