Woodbridge Antiques has dated this piece to the 1950s.
There is a good fastening pin on the back.

A lovely addition to any collection of vintage Scandinavian designer jewellery, this is just so wearable and has great mid century modern appeal.
Condition: In super condition, no chips to the enamel, and the vermeil finish is all intact. Period: 1950's
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Measurements: Height: 3 cm Width 3.9 cm Depth: 1 cm Weight: 8 grams Weights and measurements are approximate.
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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