Erbium iron garnet is a technologically important material with potential use in quantum computing. The predicted presence of a magnetic resonance and an optically active erbium ion transitions points to its possible use coupling a short-range electromagnetic superconducting quantum-bit control system and a long-range fiber-optic communication system. This could relax some of the size constraints on quantum computers thereby increasing the number of addressable quantum-bits available to a single computer. Erbium iron garnet has a ferrimagnetic ground state which has been studied extensively. Its magnetic excitations, however, remain largely unexplored. This proposed measurement of the magnetic excitations of erbium iron garnet will determine its magnetic interactions, which will provide crucial constraints for anyone hoping to exploit its properties for quantum computing.