Disclosed herein is a method for exfoliating a laminar material to form an exfoliated material, in which the laminar material is ultrasonicated in a solution of a surfactant for sufficient time to form the exfoliated material. At all times during the ultrasonication the concentration of the surfactant in the solution is maintained sufficient to form a complete monolayer on the surfaces of the laminar material and the exfoliated material in the solution, or sufficient to sterically stabilize the laminar and exfoliated materials against aggregation.

A method of making a synthetic hectorite-type mineral is described, along with its resulting physical and rheological properties. The synthetic hectorite-type mineral is a 2:1 phyllosilicate essentially free of aluminum, and having a trioctahedral structure with Mg2+ and Li+ occupying octahedral sites. As a hydrogel, the synthetic hectorite-type mineral has a swell index of greater than 55 mL, and a yield point of greater than 290 Pa. The method of making uses a MgO/MgCO3 buffer system, with heating for about 2 hours at temperatures of no higher than 300 C. and pressures of no higher than 600 psi.