Abstract: A method and apparatus for manufacturing one phase of a silica crucible including controlling the filling of a hollow mold of cylindrical shape, which rotates about its vertical axis, with grains of crystallized quartz. The grains of material are continuously introduced into the mold and are deposited on or near the lateral wall face of the mold in the form of a cylindrical layer, E, of internal radius R. A beam of light is directed to form a luminous spot on the summit of the layer from the commencement of its formation and the radial displacement of the spot on the layer is observed. The height at which the grains are introduced and the height of the trajectory of the luminous beam are modified as a function of the position of the luminous spot relative to determined reference points.