I've come across many gold-mining brooches, although they are now hard to come by, but a lapel or stick-pin is unusual. My theory is that most of these were made in Birmingham, the 19th century centre of inexpensive jewellery making, and shipped out to gold-miners in South Africa, Australia and America. This was, and is, an inexpensive little item. Whilst the head seems to be 9ct, the diamond is paste, and the pin is gilt-metal. Nevertheless, it is an amusing an inexpensive little item which might make a fun gift for a girl-friend - or maybe after the implication she will never speak to you again!