A stunning example of an iridescent ammonite fossil of the species Psiloceras planorbis from North Somerset, UK.
The piece of limestone matrix measures 146 mm (5.8 inches) across and contains two ammonites, which measure 55 mm and 38 mm. The ammonites are very well preserved and have been prepared out of the rock to reveal the shells, which display some subtle iridescent colours that change depending on the angle that the fossil is viewed at with a pearlescent sheen with flashes of red. The fossil weighs 402 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.