YES I noticed that too :-) I thought it was plastic, but it is not, it could be bone, but i'm not sure. Is ivory possible? And is this shape totaly out of context? It seems like an added element but unless I'm mistaken I have seen some swords with this part missing and it's like a grove in the scabbard. So is it a missing piece replaced later or is it possible to have something not round? Because the rest of the scabbard looks good to me.