Black sawn ammonite

This black sawn ammonite (Ammonoidea), an extinct subclass of cephalopod molluscs, is presented here in a majestic cross-section. This rare specimen has been meticulously sawn in two and polished to reveal the intimacy of its internal structure: a perfect sequence of growth chambers (or septas) mineralised by deep black sediments and dark calcite, perfectly illustrating the logarithmic spiral and sacred geometry of nature.