Laser interferometer GW detectors require the test mass to have very high Q-factor normal modes to minimize thermal,noise. There have been proposed two types of test mass suspension for advanced interferometers: silica or sapphire wires and membrane flexure suspensions. However, the grooves in the test mass which are required for flexure suspensions could degrade the resonance Q-factor of the test mass. We present Q-factor measurements of a suspended 4.5 kg sapphire test mass. issues associated with the fabrication and implementation of such suspensions are discussed. Results provide strong evidence that grooves cut in sapphire have a negligible effect on the test mass Q-factor. However, suspension losses associated with bad surface contact of the flexure element do introduce significant losses.