The Union officer above has a strange pin on his coat.  It looks like the profile of a person but we can't tell who it may be.  We're not aware of any regiments which wore pins like this, so it remains a mystery to us.  We can tell he is an officer however by the gold shoulder straps on his shoulders, although his exact rank is obscured in the image.  We also can tell he is in the infantry by the hunting horn insignia on his hat which was the symbol for infantry before crossed rifles.