The Mössbauer effect can sometimes be used to determine the relative abundances of different phases for a given element in a sample. For example, a radioactive element bound in a silicon-based glass will have a different spectrum from the same element in a (frozen) aqueous glass or in crystalline hydrates. Also, small diffusion constants [10-10 < D (cm2/s) < 10-7] can be measured for a few elements.