Andrew Cox Antiques has dated this piece to the 1920s.
The enamel is mounted on a rotating silver back and the pin is made from steel. A lovely example, dimensions below.

Postage and Packing :- £8.00 UK
£10.00 Worldwide
Condition :- Excellent, with no damage to the silver or enamel. The steel pin is a little blemished, commensurate with age and use.
Hallmarks :- Continental mark along with Sterling Silver mark.
Date :- Circa 1920.
Height :- 16.5 cms.
Diameter of mount :- 2.3 cms.
Andrew Cox Antiques has dated this piece to the 1920s.
Specialists in quality antique silver, glassware, jewellery and object de vertu
You can view the stock and full dealer information on the Andrew Cox Antiques Profile Page