A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 155 mm (6.1 inches) wide and the ammonite measures 78 mm (3.1 inches). The shell, which represents just over half of the ammonite, sits in the piece of limestone matrix in which it was found that has been shaped and has a cut-flat base and custom plaster wedge on the back to allow it to be displayed freely standing. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell. The shell displays some beautiful rainbow iridescence with deep red and copper colours that appear as the viewing angle changes.
These fossils are highly sought after and very hard to find. They are preserved in the same way as the famous Canadian "Ammolite" ammonites that are turned into valuable gemstones. The fossil weighs 340 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.