At first glance, your button looks a lot like a Confederate Officer button. But there is no EXACT match for its emblem's details in any of the reference-books on civil war buttons. Therefore it is almost 100%-certainly a modern era "military motif" civilian-clothing "Fashion" button.
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You did not tell us anything about your button's size, nor its construction. Does it have an iron back, or a brass back, and does it have any maker's mark (like a compnay name) on its back? Well-focused closeup photos of its front AND back would have been helpful for confirming the button's identification. http://www.treasurenet.com/forums/what/136849-please-read-before-posting-items-what.html