It is generally considered a suspender buckle but the were also used for vest buckles and waist adjuster buckles on pants. Because it has sharpened tines it will date from the late 1840's up to the early 1870's. Some have patent dates on them. After the early 1870's that type of buckle was phased out for more popular styles (as a general rule again). If you ever dig one that has an animal motif or a person motif on them then they will date around the turn of the century. Sometimes people claim that they are civil war era but they are not.