A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 185 mm (7.3 inches) across and contains two ammonites that measure 110 mm and 70 mm, which is large for this species. The shells sit in a piece of limestone matrix that has been shaped for display. The ammonites are well preserved and have been prepared out of the rock to reveal the whole shells. The shells display stunning iridescence, showing all of the colours of the rainbow that change as the angle of light changes. There are some natural geological faults that run through the matrix. These will have occurred over the millions of years while the rock was underground and add another level of interest to the piece. It has a cut-flat base to allow it to stand freely for display purposes in multiple ways.
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 880 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.