THE HISTORY OF BENTONITE
Bentonite is a naturally occurring mineral, 90 million years old. The story of bentonite started in volcanoes hundreds of million years ago when the molten lava was ejected (often explosively) spreading volcanic ash over most of the existing earth.
This violent start for the bentonite mineral was only the beginning. As this ash settled to the earth, it was eroded by rain and wind to the lowest resting place it could find, namely, the bottom of a body of water. And there it sat. The inland seas acted as huge collection pots for sediment. Over time the volcanic sediments built up to form multiple layers of various depths.
As the inland seas started to dry up, the dissolved minerals started to concentrate which continually forced more and more chemicals and compounds to share less and less liquid space. This concentration made elements such as sodium freely available to react with the silicates, aluminum, and magnesium that constitute the backbone of the bentonite molecules.
This sodium is what makes sodium bentonite the very different and remarkable material that it is. Other forms of bentonite are also available, but these mostly have high concentrations of calcium (Fuller’s earth), which give these bentonites different properties (substantially less sealing properties when hydrated).