This is a wonderful example of Edwardian jewellery. Beautifully made, and very well preserved. 
A gorgeous heart shaped citrine (of approx 19 carats!) Is surrounded by a bezel of tiny split pearls, with a pearl set bale.  This is an excellent size, important, without being too big to wear. 
Full UK hallmark for 9ct gold,  Chester, 1909, by makers GE Walton & Co. 
Weight approx 6.09g 
Total drop approx 30mm
Width approx 23mm
Citrine calculated to weigh approx 19ct
Excellent antique condition