The world crystal production is estimated at more than 20 000 tons per year, of
which the largest fraction of about 60 % are semiconductors silicon, GaAs, InP,
GaP, CdTe and its alloys. As can be seen in Figure 1.4 , optical crystals, scintillator
crystals, and acousto-optic crystals have about equal shares of 10 %, whereas
laser and nonlinear-optic crystals and crystals for jewelry and watch industry have
shares of a few % only. This scale of crystal production and the fact that most