A Victorian rock crystal and diamond pendant, late 19th century

A Victorian rock crystal and diamond pendant, late 19th century, decorated with the monogram 'ES' accented with rose-cut diamonds and inset into an oval rock crystal cabochon framed by old circular-cut, single-cut and rose-cut diamonds in alternating collet and square settings mounted in silver and gold, suspended from a fine link silver chain, converted from a brooch, chain stamped 925, pendant length excluding bail 3cm, chain length 44cm