A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 125 mm (4.9 inches) across and the ammonite measures 76 mm, which is large for this species. The shell sits in the original limestone matrix in which it was found: a thin piece of natural shale. The ammonite is very well preserved and has been prepared out of the rock to reveal the shell. The shell displays some beautiful multicoloured iridescence with different green, blue, and copper that appear as the viewing angle changes. This one really has spectacular colours. This one does not stand feely by itself but would make a great drawer fossil or display fossil if it is placed on a stand. A crack in the matrix has been repaired.
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 88 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.