i'm looking at some coins that show green patina on their surface (like the one shown below). Do you have any?.. what's your take on these types?..
If it isn't a fourree with a break in the plating, then it it was probably buried in contact with a coin or other metal object containing copper, and what you see is a surface deposit.
My limited experience suggests it can be quite tightly attached and is best not to try to remove. This Domitian denarius is not plated but the copper is on the surface of the silver. Small scrapes in the copper shows silver below. I suspect it was once green but was cleaned harshly revealing the copper that had patinated green. My best guess is that it was hoarded with copper coins as TIF suggested.
I also have a green Septimius Severus denarius ( one that came in an uncleaned hoard ) I'm assuming the seller didn't notice it as it looked more like a semis then a silver coin. Not really worth showing as it is completely green!
I think it is DOO-DOO! Surface deposit from the Elephant RR Julius Caesar AR Denarius 49 BCE Traveling Mint Elephant-Pontificates Sear 1399 Craw 443-1 (Copper surface deposit, probly from coin cache.)
The silver content of some denarii by this time is low enough that some can tone to look like bronzes. Worse are the so called Limes denarii which are copper alloy and can patinate just as should a bronze coin. The ones shown above with spotty green are a different thing. Limes:
..ah, that explains that...very good @TIF , @dougsmit ..haha...and of course sir @Alegandron ><..thank you very and hey @ancient coin hunter ..let's see it!
I love the green gunk on my .POSTUMUS, ROMANO-GALLIC EMPEROR, 261 AD, 21MM, 3.85GM GALLEY LEFT. RIC 73.
I'll try to dig it out of the mayonnaise jar of duplicate LRBs and take a photo. Probably won't get to it til tomorrow morning. IIRC it appears to be a silver denarius that has gone bad, but it could be a limes denarius, which might provide a better explanation.
Fun coin and thread @ominus1! I'm itching to see your coins obverse. Here Is a Sept that I consider my best/fav at least partially due to that lovely near neon pea green cabinet patina.
Green deposits, or 'greenies', on silver denarii are not all that uncommon. I usually leave them alone.
Green...be gone... Before After Postumus, 259-268 AD antoninianus, 20 mm, 3.2 gm, Cologne Obv: IMP C POSTVMVS PF AVG Radiate, draped and cuirassed bust right Rev: PROVIDENTIA AVG, Providentia standing left holding globe and transverse scepter Only coin from my collection that was ever cleaned. @YOC was kind enough to clean mine...cool results (my bad pic).
Some of these result from deposits, others from having low silver contents. Very common on Severan denarii, for instance. On the other hand, this is a Trajan drachm from Bostra that's in my collection. I can tell that it's good quality silver, but it is very dark and lightly cleaned, so you'll see traces of green around some of the features. On the other hand, what little silver content this Hadrian tetradrachm from Alexandria once had has long since leached away. I'd be very curious to know the metal content.
