Oh my, look at this fancy absolutely gorgeous peacock feather embellishment for a hat.  From decades ago, the luminous colors of each of the feathers makes this an outstanding trim for those spectacular brimmed hats from the Edwardian era. 

It was a never used feather found in a long ago closed millinery shop and has been in my own collection since.  Alas, it is time to let someone else enjoy the beauty.

As you note, the feather is curved to fit the brim of a hat. 

It is 17" long x 5" at the widest point x 2-1/2" at the narrow point.  It is covered with the blue and brown feathers on the top side.  Some of the brown are situated under the blue.  Others on the top surface.  The back of the piece is covered in mostly green.  

Condition:  At the narrow edge, as noted from the photo, a loss of a few brown feathers (or perhaps they were blue over the brown).   

Beautiful for millinery, crafting, costume or theater work....or just to admire a beauty of the past.