Such as imitation jewelry. In the 17th century, the English city of Birmingham, also locally pronounced Brummagem, was a noted source for counterfeit coins -- as well as metalwork that attempted to rival Londonwares. Later, in the early Industrial Revolution, it bacame known as a center for cheap mass-produced goods (much like China now and Japan two generations ago). The city's name was used as descriptive of like goods all through this time. This negative sense was still in use in the UK early last century, but has since died out there and survives only in the US and Australia.
That broach, my dear friend, is paste -- brummagem -- a fake.