Thanks to its layered "batch" structure, mountain soap has the ability to absorb water, swell strongly and has pronounced sorption properties.

The name "mountain soap" is not so much a metaphor, which is quite often found in mineralogy, as a simple statement of the soapy properties of the mineral, as well as the systematic use that it has had for thousands of years.

[4]: 79  On the one hand, this type of clay received its trivial name from its property of softening in water and forming with it a viscous and greasy substance to the touch, similar to thickly diluted soap.

The modern use of bentonites in industrial production, construction and even as a food additive is based on their high thermal stability, binding ability, as well as catalytic and adsorption activity.

Old authors of the 18th-19th centuries, describing the properties of mountain soap, unanimously note that it is opaque, not sticky, convenient for writing, and also soft when wetted, lathers well and sticks strongly to the tongue.

[5]: 95 It is clear that the specific characteristics of mountain soap are associated, first of all, with the breadth of coverage of regional forms and varieties that a particular author included in his review.

In particular, Spassky separately mentions that the external properties of mountain soap, used in the Kazan and Irkutsk governorates, and especially in the Crimea under the name kil, are generally similar to those described here, however, the chemical composition of each of these differences has not yet been precisely determined.

Talking about his travels through Northern Iran, he notices that different types of fatty clay, which replaces soap for the poor population when washing clothes, are found in abundance in all the nearby mountains.