Very low density eutectic Ca72Mg28 at.% metallic glass was produced by a rapid solidification melt-spinning process. The glass is considered as being a precursor of more complex ternary Ca-Mg-Zn alloys consisting solely of biocompatible elements with the view to its potential use as bioresorbable alloy for orthopaedic applications. Density, elastic modulus, hydrogen storage capacity, thermal properties of the metallic glass, such as the glass transition, crystallization and melting temperatures, as well as heats of crystallization and melting are reported. The devitrification process of the amorphous alloy up to its melt is fully described.