A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 77 mm (3 inches) across and contains a partial ammonite shell. 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 45 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.