A stunning example of a highly pyritised ammonite fossil of the species Crucilobiceras densinodulum from the world-famous Jurassic Coast beach of Charmouth, Dorset UK.
The fossil measures 38 mm (1.5 inches) across with matrix. The main ammonite shell is exposed in the centre of the matrix, but the matrix itself is actually the crushed outer whorls of the ammonite that was covered in "bubble" pyrite during the fossilisation process. These ammonites are becoming much harder to find these days due to lack of erosion of the right layers of rock.
Around 196 million years old, this fossil would make a wonderful addition to any collection.