In September 1998, the CMS electromagnetic calorimeter entered into its con
struction phase. Since that time, more than 2000 crystals have been produce
d by Bogoroditsk Techno-Chemical Plant (BTCP) in Russia and analysed at CER
N. An overview about mechanical and optical properties as well as radiation
hardness characteristics of these crystals will be presented. (C) 2000 Els
evier Science B.V. All rights reserved.