A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 136 mm (5.4 inches) wide and the ammonite measures 82 mm (3.21 inches). The shell, which represents half of the ammonite, sits in a piece of limestone matrix that has been shaped and has a cut-flat base 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 orange colours that appear as the viewing angle changes. This one really has spectacular colours.
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 140 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.