The results of absorption saturation measurements in the visible on ch
romium-doped Y2SiO5, Gd2SiO5 and Mg2SiO4 crystals are reported. The cr
oss-sections for ground state and excited state absorption of Cr4+ ion
in distorted tetrahedral sites are estimated at 694 nm. Saturable abs
orber Q-switching of a ruby laser using Cr-doped Y2SiO5 and Mg2SiO4 is
described.