There is no doubt this was a ladies fob. She would have used it to seal her correspondence. The metal is Pinchbeck, an ingenious alloy invented in the 18th c to imitate 18k gold. The seal is Purple glass carved with the name Mary Ann.
I have a love for fobs and try to always have a nice selection. They make wonderful pendants and layering pieces.
Materials: Pinchbeck, Amethyst Glass.
Measurements: 19.1mm tall. 15.4mm x 13.5mm across the base.
Era: Early 1800's
Condition: Good for its age with some wear.