Leilão Bidspirit | A large, split and polished

A large, split and polished ammonite fossil. From the Cretaceous period, about 66 million years ago. Country of origin: Madagascar. - Without the display stand. Height 13 cm.!!! The fossil shows the characteristic twisted structure, based on a precise growth pattern known in nature as part of the Fibonacci series (”Golden Ratio”). The internal cavities of the shell (the chambers in which the creature lived) were filled over millions of years with various minerals such as calcite, which give them the unique brown and golden hues. The twisted and branched lines visible on the surface are the suture lines connecting the partitions of the internal chambers and the outer wall of the shell. This complex pattern (resembling oak leaves) is very characteristic of advanced genera such as Cleoniceras