Durania ehrenbergii
Miocene
Braunkohle Lignite
Adendorf, Rhineland Germany.

13mm fruit from coal deposit.

Durania is a plant genus based on an extinct Oligocene fruit/seed from the sweetleaf family Symplocaceae, from the Oligocene of Germany but one researcher later identified the fruit as belonging to the modern genus Rehderodendron from the Family Styracaceae which includes the silverbell tree.  It’s unclear if this has become the prevailing view.