A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 66 mm (2.6 inches) tall and the ammonite measures 18 mm. The shell sits in the original limestone matrix in which it was found that has been shaped and has a cut-flat base for display. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell. The shell displays some stunning iridescence with most of the colours of the rainbow appearing as the viewing angle changes.
These fossils are highly sought after and very hard to find, especially complete like this. They are preserved in the same way as the famous Canadian "Ammolite" ammonites that are turned into valuable gemstones. The fossil weighs 40 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.