[en] Quartz (SiO₂) glass was implanted with 5 x 10¹⁶⁵⁷Fe ions/cm² at a substrate temperature of 500 deg C, and annealed at temperatures between 700 and 950 deg C. The implanted and annealed plates were characterized by conversion electron Moessbauer spectroscopy (CEMS), and measured by a Kerr effect magnetometer or a vibration sample magnetometer. Kerr effect measurement of as-implanted SiO₂ glass showed ferromagnetism at room temperature. CEM spectrum of the as-implanted glass consisted of magnetic relaxation peaks of finely dispersed metallic Fe species, and paramagnetic doublets of Fe³⁺ and Fe²⁺ species. The sample heated at 700 deg C contained large grains of metallic Fe and a lot of oxidation products of Fe²⁺ species. After oxidation at temperatures higher than 800 deg C, the samples showed also ferromagnetism, which was attributed mainly to ferromagnetic ε-Fe₂O₃ precipitated in SiO₂ matrix. Small amounts of α-Fe₂O₃ were produced at 950 deg C. The results suggest that ion implantation and oxidation make a transparent ferromagnetic glass possible. (author)