A stunning example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 190 mm (7.4 inches) tall and contains two ammonites, the largest of which measures 92 mm, which is large for this species, and the smallest of which measures 20 mm, making it a juvenile of the species. The shell sits in the original limestone matrix in which it was found that has been split to reveal both the positive ammonite shell and the negative impressed (it has been "popped" open). This is rare in these fossils as they are very hard to split like this, making it a unique example.
The ammonites are very well preserved and have been prepared out of the rock to fully reveal their detail. They display some beautiful iridescence that change as the viewing angle changes, with copper and gold colours dominating with flashes of green and red. The combined weight of both piece of matrix is 1020 grams.
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. These fossils make great unusual gifts and each one is totally unique.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.