Original CDV of a group of four young people, the seated woman wearing a mourning dress and holding a handkerchief (or letter?) in her lap... given the time period, circa 1864-1865, it's possible she was in mourning for a soldier boyfriend or husband who was killed in the war. Note that the standing girl next to her has very similar facial features, and was probably the seated girl's sister, but she is not in mourning attire... which is why I believe it was likely a boyfriend/husband.
On the back of this CDV is an Erie, PA studio imprint and a cancelled 2-cent Civil War revenue stamp. Very good antique condition overall.. 4" x 2.5".