Framed Baroque portrait miniature of a lady

Code: 11731

This is a nice 17th-century portrait of an unknown lady. She is painted on what appears to be metal (copper?) in oils and is set into a glazed metal frame. The condition is good, minor losses to the paint in places and much of the gilding has worn on the frame. I cant see a signature and the sitter is not named. Judging from the hairstyle and brooch, I would date her to the 1660's.

OBJECT: Portrait Miniature

MATERIAL: Copper - Oils

CULTURE: Baroque/Stuart

DATE: c. 1660 - 1680 AD

SIZE: 76mm (with suspension loop) x 51mm x 11.71mm thick 

WEIGHT: 58.27 grams

PROVENANCE: Formerly in a private collection. London.