[en] The electromagnetic calorimeter of the CMS experiment is now entering the construction phase. Consequently the crystal production will soon start. The preproduction phase which started in august 1998, is foreseen to allow for further optimisation of the final crystal production scheme. A general overview about the quality and characteristics of the first large batch of the preproduction crystals will be given and the results will be discussed with respect to the final production requirements needed for high resolution calorimetry for CMS