A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 160 mm (6.3 inches) tall and the ammonite measures 93 mm, which is large for this species. The shell sits in the original 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. The shell displays some beautiful multi-coloured iridescence with most of the colours of the rainbow that appear as the viewing angle changes, with copper and red tones dominating. The matrix has a cut-flat base and plaster backing to allow it to stand freely for display.
These fossils are highly sought after and very hard to find, especially complete like this. They are preserved in the same way as the famous Canadian "Ammolite" ammonites that are turned into valuable gemstones. The fossil weighs 600 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.