A method for forming a monolithic heterogeneous crystal comprising heating and pressurizing an aqueous solution held within a reactor to develop a temperature differential between a first zone of the reactor and a second zone of the reactor, the reactor containing a garnet forming feedstock in the first zone and a garnet seed crystal in the second zone, the feedstock forming the same garnet as the garnet of the seed crystal, the feedstock including a source for a saturable absorber ion, wherein upon said heating and pressurizing growth of a garnet Q-switch crystal region is initiated on the garnet seed crystal to form a monolithic garnet product crystal, the composition of the Q-switch crystal region differing from the composition of the seed crystal such that the monolithic garnet product crystal is heterogeneous.