A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 95 mm (3.71 inches) wide and the ammonite measures 76 mm, which is a good size for this species. The shell sits in the original piece of limestone matrix in which it was found. 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. Part of the centre of the shell is missing, but this does little to detract from this wonderful specimen. There is also an unusual geological fault line running through the shell meaning that a piece of it sits on a slightly different level to the rest, adding to the uniqueness of the specimen. It has a cut-flat base and custom plaster wedge on the back 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 250 grams and is a real beauty in the flesh.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.