Bentonite often contain a small amount of illite, kaolinite, halloysite, chlorite, zeolite, quartz, feldspar, calcite, etc. Some bentonites are as loose as soil, and some are dense and hard. The main chemical components are silicon dioxide, aluminum oxide and water, and also contain iron, magnesium, calcium, sodium, potassium and other elements.
The main mineral component is montmorillonite, with a content of 85-90%. Some properties of bentonite are also determined by montmorillonite. Montmorillonite can be in various colors such as yellow-green, yellow-white, gray, white and so on. It can be dense block or loose soil. There is a slippery feeling when rubbing with fingers, and the volume of the small block will expand several times to 20-30 times after adding water, and it will be suspended in water, and it will be paste when there is little water.