A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 155 mm (6.1 inches) tall and the ammonite measures 76 mm, which is a good size for this species. The shell sits in the original limestone 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 beautiful green iridescence that changes as the viewing angle changes. Green is the most sought-after colour on these fossils and they are rarely found in this condition. There is also a possible predation bite in the outer whorl adding to the interest in this fossil.
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 400 grams. 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.