permineralizations

Permineralization is a fossilization process in which mineral-rich groundwater permeates the porous tissues of buried organisms and deposits minerals within their internal spaces. The minerals precipitate in cavities such as cell lumens and vascular networks, gradually turning the remains into a durable, mineral-rich fossil. Depending on the conditions, the original organic matrix may be preserved or only its internal framework retained as mineral infill.

Common minerals involved include silica, calcite, pyrite, and phosphate. Silica is especially associated with petrified wood, preserving growth rings and sometimes cellular details. Pyrite can yield bronze-golden fossils, while phosphate can preserve bone and tooth microstructure.

The process requires porous tissues and groundwater rich in dissolved minerals, usually occurring during diagenesis after burial in sediment. Low-oxygen environments help slow decay and promote mineral precipitation, aiding preservation of internal anatomy.

Permineralization is one of several pathways of fossilization and is distinct from full replacement, where original material is chemically replaced by minerals. In permineralization, the organic framework is often retained and reinforced by mineral infill, yielding detailed interior preservation that is valuable for anatomical and ecological studies.