A method of making a rheology modified aqueous composition, particularly useful for drilling, milling and mining applications, is disclosed. The method includes admixing, with a clay and water, a material or materials whose constituents substantially conform to the proportions of the empirical formula M′mM″n(OH)(2m+3n+qa+br)(Aq)a(Br)b.xH2O, where M′ is a divalent metal cation, M″ is a trivalent metal cation, A and B are anions, and a, b, m, n, q, r, and x are defined herein. Calcined hydrotalcite and hydrotalcite-like materials are particularly preferred as starting materials. Optionally, an aluminum oxide, a nitrogen-containing compound, or both may be added. The resulting composition is preferably an elastic solid exhibiting stress-dependent fluidity, desirable temperature resistance, lubricity, inhibition of reactivity, relatively low cost, and pressure resistance. A dry composition and method of making are also disclosed.