Multi-scale study of the role of the biofilm in the formation of minerals and fabrics in calcareous tufa

Organomineral nanospheres successively agglutinate to form irregular to rod-shaped crystal aggregates, 100-200 nm in size, that with their further agglutination create two basic types of larger, more ordered, crystal structure: polyhedrons in the range of 1-2 μm, and minute triads of calcite fibres varying in length from ~ 0.4 (short triads) to ~ 1 μm (long triads). Basic crystal structures coalesce to form larger crystals (mainly tetrahedrons tens of microns in size) that constitute the micro-columns.