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A set of procedures was developed for the electron probe X-ray microanalysis (EPMA) of fish and animal bone tissues, solid snow sediments, and coal ashes. Various sample-preparation procedures and two variants of the optimum conditions for analytical measurements were considered. In calculating analyte concentrations, matrix effects were taken into account using ZAF methods and the function of generated X-ray distribution with depth, namely, by the PAP method and by adding a joint correction for absorption and atomic number within a biexponential Φ(ρz) model. For EPMA of small fractions 1–5 μm in size, an approach was proposed that takes into account the test sample size using an analytical expression. In calculations of concentrations for micron-sized particles, this approach can lower the relative deviation from the stoichiometric composition from 36.8% to 22.2%. In developing the procedures, the potentialities of the proposed technique were assessed and its metrological characteristics were determined.

Crystallization of the beryllium indialite (Mg2BeAl2Si6O18) melt is investigated. Crystallization at high cooling rates and thermal gradients gives metastable compounds (petalite structural type, mullite, sapphririne); under slow cooling and in the absence of thermal gradients, stable beryllium indialite crystallizes. The main reason for that, suggested from structural motifs of the formed phases, is that most of the magnesium exists in the melt as MgO4 in the former case or as MgO6 in the latter case. The same (petalite) structural type crystallizes from liquates differing only in a ratio of type-forming elements. The composition of metastable phases is determined.