High-pressure micro-Brillouin scattering is employed to investigate the pressure dependence of the sound velocity, refractive index, equation of state, and mechanical properties of amorphous BeH2. The refractive index n has been determined by using two scattering geometries (70° and 180°). The equation of state is deduced from the pressure dependences of the sound velocity. The bulk modulus is 14.2 (±3.0) GPa and its pressure derivative is 5.3 (±0.5). The polarizability is calculated from the refractive index and the density of the material. It increases with pressure while Poisson’s ratio decreases with pressure. [ABSTRACT FROM AUTHOR]