Insignia identification

[lewjian]

Hello everyone, I would like to show you a photot of an Ehrhardt member.
It's been puzzling me since day one what is the insignia he is wearing next to the Ehrhardt Merits Badge and wound badge. It looks like a pin with crown at the top.
Any idea what the insignia could be?
Could it be some sort of regiment badge from his WWI unit? Does the Pickelhaube insignia tells which unit he was from?

[lewjian]

Zoom up of the unknown badge

[lewjian]

And the Pickelhaube