Some 20 years ago I bought
part of a
collection of
rings found near Rhenen in
Holland. It is a place where habitation in the centuries just before the
Romans was present. From the beginning of our era onwards there was a very limited output of
Celtic coins, mostly in bronze, but also in silver and gold (in
German: 'Regenbogenschuesselchen' =rainbowcups). So the
provenance of the
rings could be OK. In total some 300
had been found.
The large ones, up tp 45 mms, are
cast and filed; the smaller ones cut out of a plate. Apparently they fixed a
fine chain in the middle of a plate and incised circles from both sides, so that a ring would come free. The next ring would be one shackle smaller, etc. The smallest one I've got is only 13 mms.
Information and literature on the subject of these plain
rings seems to lack. On the (Gallic)
rings with knobs and notches, as well as spoked wheels, there is
plenty.
Good luck with your investigation.