The elastic constants of non‐metamict and partly metamict (density 4.531 g.cm−3) zircon have been determined at room temperature and pressure by means of ultrasonic phase comparison method demonstrating the large effect of radiation damage on the elastic constants of zircon. Using the elastic constants data of nonmetamict and metamict zircons various isotropic, anisotropic and polycrystalIine properties have been derived, including thermal and axial Gru¨neisen parameters, Young's and the shear moduli, average longitudinal and shear sound velocities and the Debye temperature. These values are compared with the available data in the literature.