Posted 01/04/2012 6:50 pm
I have seen only or two 'greenish' silver Roman coins in the whole of my collecting experence. I do have a denarius of Geta that is dark like this one, and a Nilus Egyptian tetradrachm of Hadrian that is also very dark, but they don't have a slightly greenish tinge.
The silver alloy used for almost all of Hadrian's denarii was reasonably good at around 80% purity. Having said that, even the official Roman mints were capable of producing denarii with dodgy alloy, but they are very scarce, and I have not seen a silver denarius of Hadrian like this one before.
Most silver coins if they present dark, are heavily patinated with sulphides and / or chlorides of silver. If this coin is simialr to the other two mentioned, they may have come from the same burial site. I would certainly make an inquiry to the seller about this. The greenish tinge may have been helped by the dark patination.
I notice that there a few high points on the coin where the subsrate metal shows. It would be good if you could get a 20 x magnification loupe that does dot suffer from color abberation, onto those areas. To make good judgement, skill and experience is needed with such a loupe. I use one for the internal examination of cut gemstones.
Hope this helps.
The silver alloy used for almost all of Hadrian's denarii was reasonably good at around 80% purity. Having said that, even the official Roman mints were capable of producing denarii with dodgy alloy, but they are very scarce, and I have not seen a silver denarius of Hadrian like this one before.
Most silver coins if they present dark, are heavily patinated with sulphides and / or chlorides of silver. If this coin is simialr to the other two mentioned, they may have come from the same burial site. I would certainly make an inquiry to the seller about this. The greenish tinge may have been helped by the dark patination.
I notice that there a few high points on the coin where the subsrate metal shows. It would be good if you could get a 20 x magnification loupe that does dot suffer from color abberation, onto those areas. To make good judgement, skill and experience is needed with such a loupe. I use one for the internal examination of cut gemstones.
Hope this helps.
