A Putative Coiled Molluscan Fossil in Polished Carbonate Flooring at Sharif University of Technology: A Preliminary Photographic Case Study

Fossil-bearing building stones provide accessible records of ancient biological activity and subsequent geological modification, although their interpretation is frequently constrained by incomplete provenance and the geometry of exposed surfaces. This study presents a qualitative examination of a spiral structure photographed by the author in the stone flooring of a room at the Faculty of Computer Engineering, Sharif University of Technology, Tehran, Iran. The structure consists of nested, curved bands distinguished by contrasts in colour and apparent texture within a heterogeneous, polished stone. Its coherent coiling is consistent with a section through a fossil shell, with a coiled mollusc representing a plausible biological interpretation. However, diagnostic features required to distinguish confidently between a gastropod and a coiled cephalopod are not resolved. The surrounding stone contains pale linear features and irregular dark seams that may record mineral infilling, fracturing, or pressure dissolution, but their origins remain unverified. Although described using the commercial term “marble,” the material is provisionally interpreted as a carbonate dimension stone containing a putative fossil, potentially limestone or partially recrystallized limestone, rather than demonstrably metamorphic marble. Neither geological age nor quarry provenance can be established from the photograph. The study distinguishes direct observations from interpretive hypotheses and proposes a minimally invasive programme of documentation and petrographic investigation.