The effect of α-recoil damage in natural zircon has been studied by infrared spectra of the silicate vibrations, single crystal x-ray diffraction, and polarized visible and near infrared spectra of absorptions due to tetravalent uranium. Contrary to some previously expressed views, α-recoil damage in natural zircon appears to be a progressive process, with increasing α-recoil dosage. No crystalline phases of zirconia or silica were detected by x-ray diffraction and measurements of U4+spectra, in any but some very severely damaged zircons. The end product, in the limit of very high α-recoil doses, would seem to be a glass, rather than a mixture of SiO2and ZrO2. The Si-O bonding in the glass would appear to be rather similar to that in vitreous SiO2.