Lot 386: A Group of Polished Pyritized Ammonite Fossils in Matrix

A collection of four polished natural history specimens featuring pyritized ammonites, likely Dactylioceras sp. or similar Jurassic species, encased in a dark mineralised matrix. The group comprises a matching split nodule forming a part and counterpart, and two individual egg-shaped nodules. The ammonites exhibit a distinctive brassy metallic lustre resulting from pyritization, which provides a sharp visual contrast against the deep black mudstone or shale matrix. Each specimen has been shaped and polished on its exterior surfaces to a high-gloss finish. These fossils are characteristic of the Upper Lias formations of the Yorkshire coast, UK, particularly those found near Whitby.