A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 153 mm (3.4 inches) tall and contains a complete ammonite that measures 75 mm. It weighs 525 grams and the matrix has been sculpted and has a cut-flat base for display.
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, which displays some beautiful subtle iridescence with a copper and bronze sheen with flashes of gold that appear as the viewing angle changes. There is an unusual natural geological fault line running through the ammonite and matrix.
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.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.