She is not a metamorphagus or a werewolf. Like her sister, she is an Animagus (Rabbit). She is often mistaken as a common house rabbit.
The only difference between her twin sister and her, is the color of their eyes. Emerald has emerald colored eyes, and Hazel has hazel colored eyes.
Hazel is relaxed, and subtle. She would always turn into a rabbit, while her sister was a owl, and hop around the house. She is a pale blonde colored rabbit with hazel eyes. Those are her physical characteristics as an animagus.