Hi My TH'ing Friends
My two cents worth says it is a 'flower button'. These are common finds here in Virginia. Many are pre and post Civil War vintage and very little to distinguish the two. Many were worn by CSA troops as that was on their cloths they wore to the war. I love buttons and have several that are similar to yours. Great find none the less. Keep digging up the good stuff.
Dave
'Digger-Dave'
THing4CSA
PS: Remember; Don't leave it in the ground!