A stunning example of an iridescent ammonite fossil of the species Psiloceras planorbis from North Somerset, UK.
The piece of limestone matrix measures 117 mm (4.6 inches) across and contains two ammonites, which measure 50 mm and 24 mm. The ammonites are well preserved and have been prepared out of the rock to reveal the details of the shells, which display some beautiful subtle iridescent colours that change depending on the angle that the fossil is viewed at with a nice red sheen. There are flashes of copper and gold in the shell. The fossil weighs 185 grams and has a cut flat base to allow it to stand freely for display.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection. These fossils are preserved in the same way as the more famous Canadian "ammolite", which is turned into valuable gemstones due to the stunning iridescence.