Found this yesterday on Long Island...Back is missing. Eagle grasping anchor, with three cannonballs, and stars, as in most Navy buttons. But the wings of the eagle are straighter, more vertical, than ones I've seen in other pics. Wondering about age. Anyone encountered a button like this?
The very weak detail of the emblem is a strong indication that it is a Civilian-clothing button, not Military. Also, the back being missing from a "Navy" button is almost always a sign of a cheaply-made Civilian "fashion" button. Sorry to have to tell you those things about your find. But I'll add that you did the smart thing by posting it for accurate identification of it. Us oldtimer diggers say "Never toss a find into the junk-box (or trashcan without checking for accurate identification ...especially when it's not made of iron or aluminum."
By the way, welcome to the What-Is-It forum. It is definitely the very best place for digger-finds identification on the Internet. You'll learn lots of good information here.
Yes, it has some age to it. The civilian-usage imitations of US Navy buttons seem to first start showing up in the very late 1800s -- and have been manufactured continually ever since then (you can still buy them today at sewing-supplies stores like JoAnn Fabrics). Because your button's back is missing, there's no way for us to know whether yours is 100 years old or 40 years old. (A couple of decades in the ground is enough to cause a brass button to look like yours does.)
I see the wings look more rounded now and I agree with CBG its an old civilian steel back fashion button made in a Navy motiff. . The back rusted away.