A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 115 mm (4.52 inches) tall and the ammonite measures 90 mm, which is large for this species. The partial shell sits in the original limestone matrix in which it was found that has been shaped for display. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell, which displays stunning iridescence, showing all of the colours of the rainbow that change as the angle of light changes, with green and orange colours dominating. It has a cut-flat base to allow it to stand freely for display purposes.
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 390 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.