A stunning example of an iridescent ammonite fossil of the species Psiloceras planorbis from North Somerset, UK.
The piece of limestone matrix measures 155 mm (6.1 inches) across and contains a single ammonite that measures 62 mm (2.4 inches), which is large for this species.
The ammonite is very well preserved and has been prepared out of the rock to reveal the shell, which displays some stunning iridescent colours that change depending on the angle that the fossil is viewed at. There is a lovely mix of orange, gold, and green colours that flash against and overall pearlescent sheen.
The shell sits in the original thin piece of limestone shale matrix in which it was found that has been shaped and has a cut-flat base that allows it to stand by itself for display. The matrix around the ammonite has been stabilised with glue, which can be seen on the back of the fossil, which is standard with these fossils. It weighs 200 grams.
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.