The scattering of acoustic ultra-wideband X-wave pulses by a nonrigid sphere is simulated for purposes of material identification and characterization. Using the backscattered spectrum of the X-wave pulses, a procedure is described for estimating the radius, speed of sound, and density of-the sphere. The effectiveness of the suggested technique is verified in the case that the peak of the X-wave is incident on the centers of the sphere, as well as for the off-center incidence case.