A stunning and perfect example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 178 mm (7 inches) wide and contains a large partial ammonite shell that measures 95 mm and sits in the original limestone matrix in which it was found. This is large for this species. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell, which displays some beautiful iridescence with the colours changing as the viewing angle changes with green, red, yellow, and copper colours present. This one has a really strong range of 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 850 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.