gold and silver heart locket pendant with diamond and rock crystal

An 18 carat gold and silver locket pendant (with detachable brooch fitting) in a stylized heart or drop shape with an elegant bow on top. In the middle is a drop shaped rock crystal incrusted with a cushion cut diamond (app. 0.9 carat I-J SI 2) and two small old cuts above and under it. Around this is a border of small rose cut diamonds and another border of larger graduating cushion cut diamonds (100 diamonds app. 5 carat in total, I-J, Si2), circa 1860, France.

weight: 21.65 grams
dimensions: 6 x 3 cm