Gadolium gallium garnet crystals substituted with Ca,Mg, and Zr and doubly-doped with Nd and Cr are grown, and their laser properties are investigated. Transparent and perfect boules measuring ψ18×60-80mm are grow n by means of Gzochralski method using iridium crucible and inducting heating. Laser rods of the size of ψ5 × 40mm are machined. The output slope efficiency obtained was 0.7. Comparison of spectroseopic properties and lattice constant of the crystal with those of GGG crystals doubly doped with Nd, Cr and substituted with a small amount of So is made and a discussion is given.