A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 54 mm (2.1 inches) across and contains a single complete ammonite that measures 23 mm (0.9 inches), making it a juvenile of this species.
The shell sits in the original limestone matrix in which it was found 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, which displays some beautiful iridescence that changes as the viewing angle changes, with most of the colours of the rainbow being present. This is about as colourful as these ammonites get! The whole piece weighs 72 grams.
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. These fossils make great unusual gifts and each one is totally unique.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.