This is a coat size infantry Eagle I button. The backmark is M. C. LILLEY & CO. / COLUMBUS O. This company manufactured military goods from at least 1876 through WWII. The button has some aged patina to it, but there is plenty of gold gilt to make it stand out. The shank is in stand up condition. The item around the button is just a case that helped me scan it...in case you were wondering.
Please email me for the shipping cost.