world war one shell

"This shell was picked up on the war fields of France by my husband's grandmother who was stranded in France when the war broke out while working in Paris as a nanny. She had to remain in France during the war and picked this shell up in the fields before she came home. I think it is an American shell. It has a bird with the words Eternal Vigilance is the price of success on the shaft, a gold star at the back and the year 1917 on the base. It is made of brass and is buckled where it exploded at the top. "