The goal is to measure coherent tunneling of perhaps ~104 magnetic spins between easy-axis-direction orientations in small ferromagnetic particles. A similar quantum rotation of the Neel vector in an antiferromagnetic particle is also expected, and would be detected by way of the uncompensated spins. Experimentally, construction of a cantilever-based torque magnetometer is underway, starting with a fiber optic interferometric displacement detection system. The first step will be magnetic measurements of the molecular magnet Mn12-acetate (microcrystals of this material have been attached to silicon microcantilevers).