A cased Victorian reverse painted crystal intaglio stick pin

A cased Victorian reverse painted crystal intaglio stick pin,
depicting a dog with collar. The circular crystal intaglio, 13.5mm diameter, with a white and black painted intaglio dog, possibly a 19th century bull terrier, to a mother-of-pearl ground, rub set in a plain mount. Marked 18. Pin lower carat, tested as approximately 9ct gold. 3.32g. Case by 'Goldsmiths' and Silversmiths' Company Ltd., 112 Regent St., London W1'
Sold for £280

Condition report:
Minor marks to the gold and the rock crystal.