A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The piece of limestone matrix measures 155 mm (6.1 inches) tall and contains one large complete ammonite that measures 80 mm (3.2 inches), which is large for this species, as well as two partial ammonite shells. The complete ammonite has an unusual predation bite in the outer whorl - this is where a Jurassic predator attacked and killed the ammonite.
The shell sits in the original matrix in which it was found that has been shaped and has a cut-flat base to allow it to be displayed freely standing. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell, which displays some truly beautiful iridescence that changes as the viewing angle changes, with most of the colours of the rainbow present. This is about as good as the colours get in these fossils! The whole piece weighs 635 grams.
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. 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.