A late 19th / early 20th century diamond and sapphire brooch

A late 19th / early 20th century diamond and sapphire brooch
The detachable heart-shaped pendant centrally-set with an oval-cut sapphire within a graduated rose-cut diamond surround in foiled closed back settings, to a later reverse with engraved motif, suspended from a rose-cut diamond bow surmount, Dutch marks, 5.0cm long
Maker's mark JRS