ABSTRACT: Chemical maps and images were made of the test of Textularia earlandi, an agglutinated foraminifera, by ESEM-EDS (Environmental Scanning Electron Microscopy-Energy Dispersive Spectrometer). The specimen is about 300μm long, comprising 17 imbricated growth chambers. In order to evaluate themass distribution along the test, mineral grain densities, as deduced through chemical mapping, as well as the volumes of 650 grains, were treated by geostatistical methods. The volume of the imbricated spheres was 3D-modelled using theMonte-Carlo method. It is calculated that the volume of the chamber grows regularly. The mass of the chambers undergo some variation due to occurrence of various proportions of minerals with different densities. The mass distribution within each chamber is smoothly distributed. Further development on other protists with various shape and geometry could be easily imagined.