On the relation between the origins of aragonite and the lattice constants, transition temperatures to calcite

Abstract

To understand the mineralogical difference between biominerals and their geological or synthetic counterparts, the lattice constants of aragonite and its transition temperatures to calcite by heating in various biotic, geological and synthetic aragonites have been measured. Among 21 aragonite specimens, the axial ratios for six marine molluscan species are considerably larger than those of abiotic ones but three fresh-water species and three land snails have similar axial ratios. On the other hand, almost biotic aragonites showed a transition temperature 60-100C lower than geological and synthetic ones, but the shells of land snails showed almost the same transition temperature.