There is also a wee bit of petrified wood on the backside.
These beauties hail from Jurassic, Lower Callovian outcrops in the Quarry of Kursk Magnetic Anomaly (51.25361,37.66944), Kursk region, Russia. Diameter ammonite 70мм.
Back in the USSR — in the mid-1980s — during the expansion and development of one of the quarries, an unusual geological formation was found. This area had been part of the seafloor around an ancient island surrounded by Jurassic Seas.
The outcrops of this geological formation turned out to be very rich in marine fossils. This ammonite block was found there years ago by the deeply awesome Emil Black. It has been many years since he has been able to collect there as the site is now closed to fossil collecting and employed solely for the processing and extraction of iron ore deposits.