A stunning and perfect example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 250 mm (9.85 inches) across at the widest point and contains two ammonites that measure 105 mm and 92 mm, which is very large for this species. The shells sit in the original limestone matrix in which they were found. The ammonites are very well preserved with the centres missing and have been prepared out of the rock to reveal the shells, which display some beautiful multicoloured iridescence with flashes of red, gold, green, and copper 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 995 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.