Looks old but hard to tell without more info. Post a pic of the front of the button as well and describe anything written on the back which will help identify it.
Well from the little info provided I can say that it is a 2 piece button, mid to late 19th century. A picture of the front will help narrow it from there
great seal button used from 1902 to present ..however if you tell us what is on the back --by the wording we can most likely tell the time frame by the makers markings