I have acquired this coin after it was brought to me at the market yesterday. It weighs about 5.25g and measures 18.8mm at the longest across. I believe it is a Celtic Stater, probably of the Durotriges tribe in South West England dating between about 100BC and 100AD. Two queries: 1. Is this attribution correct? 2. Is it right? (Ie not a fake or a later reproduction?) It appears to be mostly Bronze or other cuprous alloy, and there is a little verdigris but also red corrosion at one point on the edge. It has a pale gold surface as shown - as plating was obviously impossible at that time, it would need to have been dipped in molten metal. I have little experience of these and the books are pretty brief on the appearance of the Bronze staters - is this all likely/possible?
My understanding is that one way was to make an alloy of gold and mostly copper then bath it in an acid like vinegar or lemon juice. The copper at the surface leaches out and leaves gold on the surface that could be hammered out like gold leaf. Also perhaps gold leaf was attached in some fashion.
It's not a Durotriges stater - the horse on the reverse is wrong for them. It could be a North East coast type (based on the reverse), or Gaulish (based on the obverse), but I can't tell from the photos. Plated Celtc staters, and their remaining cores, are common. Some are contemporary forgeries, and some were probably official issues.
