A stunning example of an iridescent calcite ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The piece of limestone matrix measures 295 mm (11.65 inches) tall and contains two partial ammonites, the largest of which measures 148 mm across, which is huge for this species. The ammonites are well preserved and have been prepared out of the rock to reveal the detail of the shells, which display some nice subtle iridescence with a silver sheen. The fossil weighs 1385 grams and has a cut flat base and plaster wedge to allow it to stand freely for display.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.