A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 126 mm (5 inches) across and contains a stunning large ammonite that is split so that the positive and negative parts of the shell some away from one another or can be put back together. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell. The shell displays some beautiful multicoloured iridescence with flashes of red, gold, green, and copper that appear as the viewing angle changes. This one really has spectacular colours. There is a crack running through the ammonite that has been stabilised with glue and is strong and stable.
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 510 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.