BIRUG 39142 is a halved ammonite specimen, probably belonging to the genus *Arietites*. The interior chambers of the phragmocone (shell) can be seen in this specimen, delimited by septa and infilled with quartz.
This specimen is from Lyme Regis in Dorset, UK and dates from the Lower Jurassic. Scanning was performed using an Artec Spider 3D scanner by Courtney Szanto.