The object below is an Iron Age (Celtic or early Roman) brooch that was found near here.
It's actually bronze—not gold as the photograph makes it appear—and about 30 mm across. The style is 'La Tène III', named after La Tène in Switzerland where an enormous cache of artifacts in this characteristic style was excavated in the 19th century.
It took me a long while to work out what the geometry would have been but after looking at lots of pictures and consulting a friend I now have a reasonable idea. There would have been a pin, wound round one end to make a spring, and at the other end a catch for the pin, something like this
The missing parts being more fragile have broken off, or possibly just corroded away. Indeed it's possible the clip breaking caused the brooch to get lost, or perhaps when it broke the owner simply slung it away. It would have been the budget-friendly jewellery of its time, and very large numbers of similar brooches are found.
All the same I felt a thrill to handle it and reflect that until a few days ago no other human being had touched it for two thousand years.