Like any other raw material available on earth, clay is also composed of many types of minerals. As ceramists, we are interested in few main types of minerals found in clay namely:
- Kaolinite
- Montmorillonite
- Illite
These minerals may be found together or separately contaminated with grains of quartz and other non-clay minerals.
Out of these, KAOLINITE is the most common mineral. These minerals are made of silicon-oxygen sheets and aluminium-hydroxyl sheets which gives the plate-like character to Kaolinite minerals.
Montmorillonite mineral contains magnesium and iron atoms occupying some of the aluminium atoms. The water penetrates between the lattice layers of the minerals and seperates them. This causes Montmorillonite to exhibit swollen characteristics.
Illite (also referred to as Hydrous mica) exhibits intermediate characteristics between Montmorillonite and Mica. It has no swelling properties and sometimes with a chlorite like structure.
