Montmorillonite is a type of clay composed of aluminium silicate that forms very small particles that are not well-bonded to one another. This is why it is so soft. When in the presence of water, all types of clay swell. Montmorillonite swells even more than most types of clay, which is why it is often chosen over other types of clay in its practical uses. Montmorillonite has many different practical uses, including in the mining industry, as a soil additive, as a sealant, as a desiccant to draw water out of the air, to clean ponds, to make kitty litter and in cosmetics. Montmorillonite is a common mineral and, despite being named after Montmorillon, France, can be found all over the world, including many deposits in Australia. It is not known where this particular specimen originates from. Montmorillonite is an economically and socially significant material with a wide variety of uses. Having samples of common and important minerals allows collections, like the Burke Museum, to have a more complete view of the land on which they are located, and therefore a more complete view of heritage. This specimen is part of a larger collection of geological and mineral specimens collected from around Australia (and some parts of the world) and donated to the Burke Museum between 1868-1880. A large percentage of these specimens were collected in Victoria as part of the Geological Survey of Victoria that begun in 1852 (in response to the Gold Rush) to study and map the geology of Victoria. Collecting geological specimens was an important part of mapping and understanding the scientific makeup of the earth. Many of these specimens were sent to research and collecting organisations across Australia, including the Burke Museum, to educate and encourage further study.A solid tennis-ball sized chunk of aluminium silicate clay. It is primarily white, accented with orange and brown.burke museum, beechworth, geological, geological specimen, clay, montmorillonite