A classic Scunthorpe ammonite, Asteroceras stellare (SOWERBY, 1815) displaying calcification within the chambers which can be viewed now the shell is removed. The ammonoid has been prepared using micro-abrasive tools in a fossil laboratory workshop.
The rare ammonite with cream colour calcite (calcite is a mineral type of the quartz family), chambers between suture divisions or patterning, these are the placements where the outer chitin shell attached to the cephalopod and denote the septa placements, the internal chamber divisions. The chambers which acted as floatation chambers, being filled with water to aid diving into depth or filled with gases to pump out the water to rise through the water column.
The bronze surmount sets off the rare British ammonoid which in recent years has become a scarce type due to the closure of the commercial quarry at Conesby, near Scunthorpe, where over a decade ago one could still occasionally find these colourful high grade and sort after fossil ammonoids.