Woodbridge Antiques has dated this piece to the 1950s.
The back of the brooch is marked 'Sterling 925 S' along with the mark for the well known designer Theodore Olsen and 'Norway'. There is a good fastening clasp at the back that works well.

A perfect gift, made by a collectable designer and in fabulous condition.
Period: Circa 1950
Measurements: Height: 2.1 cm Width: 3.4 cm Weight: 5.1 grams
Weight and Measurements are approximate.
Stock Number 40792
Woodbridge Antiques has dated this piece to the 1950s.
Specialists in quality antique silver, fine jewellery & accessories
You can view the stock and full dealer information on the Woodbridge Antiques Profile Page