Gel fibres of barium M ferrite, BaFe12O19, were blow spun from an aqueous inorganic sol and calcined at temperatures up to 1200 degrees C. The ceramic fibres were shown by X-ray diffraction to be single phase crystalline M ferrite at 1000 degrees C, and surface area and porosity measurements indicated an unusually high degree of sintering at this temperature. The fibres also demonstrated a favourable grain structure of less than 0.1 mu m at this temperature and maintained a small grain size of less than 4 mu m even up to 1200 degrees C, an important factor in the magnetic properties of this material.