In the latest patch, it is written that "the material type of the ornament adapts to the material type of the helmet".

This is true for all of the Warden's ornaments (I haven't checked the other classes), except for the magnificent Daubeny ears.
I don't know wether this is a bug or a feature, but this forces our glorious Warden comunity to use golden helmets, in case we want to wear these majestic wings.

Wether or not this is a bug, I suggest to use the same material of the helmet on this ornament too.