Abstract: A simple shear device and method for its use to test stress and strain characteristics of earthen samples and powders. The shear device particularly comprises a stacked plurality of plates which are slidably movable laterally relative to one another, which plates have a hollow central area for holding a cuboidal sample and spaced first and second platens having faces at between parallel and 45.degree. relative orientation to one another, between which the plurality of plates containing the sample may be placed. A first force may be applied to the first platen urging it toward the second platen to compress the sample therebetween; a second force is applied to one of the platens to urge the platen in an angular direction relative to the direction of the first force to apply a shear force to the sample. The resulting stresses and strains in the sample are monitored when the forces are applied to the sample while confined between the platens.