This beautiful fluid shape.eeminds me of a ribbon set with pearls. Originally an Edwardian brooch,  we have converted it, adding a modern 9ct gold trace chain. 
It curves to sit at the neck beautifully, and we have made the chain adjustable so that it can worn at either 18" or 20". 
Tests as 9ct gold (chain is hallmarked) 
Weight approx 4.80g .
Chain length approx 18 - 20" adjustable. 
Width of motif approx 2" 
Excellent antique condition