AgAu Jewellery has dated this piece to the 1860s.

Metal: 9ct yellow gold.
Hallmarks: Marked for 9ct gold on the pendant. Chain fully marked for 9ct gold
Stone(s): 1 x pear cut opal (1.50ct)
Measurements: Pendant `30mm x 19mm, chain 16"/40cm,
Weight: 5.9g
Condition: Very good condition
AgAu Jewellery has dated this piece to the 1860s.
Agau jewellery offer an extensive range of 9ct and 18ct gold jewellery.
You can view the stock and full dealer information on the AgAu Jewellery Profile Page