A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 90 mm (3.55 inches) wide and contains a partial ammonite. The shell sits in the original limestone matrix in which it was found and is well preserved and has been prepared out of the rock to reveal the detail. The shell displays some beautiful rainbow-coloured iridescence with many of the colours of the rainbow that change as the viewing angle changes. Caloceras with this range of colours are very sought after.
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 45 grams. 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.