Sorry to have to tell you, your button is not a Military button. It is a 20th-Century civilian button which had an iron back that rusted out. It has showed up here in the What-Is-It? forum several timers in the past.... identified by DCMatt as a cheap modern blazer-button imitation of an antique French Republic button, with the "stylized" letters JTE in the center. Here are photos showing some in non-excavated condition, for sale on the Internet.