Dynamic fracture strengths of a representative suite of crustal rocks have been determined. The rocks investigated included silicates and carbonates of varying grain size and porosity, oil shale with several kerogen contents and orientations, and fused silica. With the exception of fused silica, fracture strengths ranged from a few tens of MPa to slightly over 100 MPa. Rate dependence of fracture stress and fracture energy appears to be important in determining the dynamic strength of rock.