Dear all,
In the river Maas near Cuijk, amateur underwater archeologists found two
Roman fubulae: one with a green and one with a black patina. The one with
the black patina also showed tiny gold-coloured spots. It was hoped and
expected that it would be a gilded silver object ? EDAX analysis, however,
revealed that the fibulae was made of bronze, covered with iron and/or
copper sulfide.The gilding turned out to be pyrite. Sofar not much of a
mystery, but I am very interested how such a patina can be formed
(environmental conditions). The bottom of the river consists of layers of
peat, sand & pebbles and clay. The fibulae are loose finds, not traceable
to a specific layer.
Can anybody please tell me where to look for a clear paper about the
formation of such a patina.
Best regards,
Peter Seinen,
Underwater archeology "Mergor in Mosam", Cuijk Holland
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