Tiber patina?

[JayAg47]

Is it a real phenomenon or just an euphemism for bronzes that were stripped of their dark patination during cleaning process? 

I think this coin represents the Tiber patina where most of the orichalcum surface is exposed.

Although please post any better examples if you have.

 

[expat]

I think it is a term used for bronze/copper coins with no real patina, but those that have toned a yellowish colour. This composition of coins will often display such popular toning when submerged for millenia in clay, mud or the sandy deposits (alluvial) in the mouths of large rivers. There is no guarantee that these coins were actually in the river. Often they exhibit a pitted surface but those with a smooth surface attract more attention.

[sand]

Hello @JayAg47. I share your amusement with the phrase "Tiber patina". I just did a Vcoins search for "Tiber patina", which resulted in the following 10 coins.

These are not my coins.

As you can see, the colors are all over the place. I also tried searching Nvmis Forvms, Coin Talk, and Forum Ancient Coins. I found a few posts about it, but nothing very authoritative. However, I didn't look very thoroughly, because I don't care very much about it, except to be amused by it. The following post is slightly interesting, because it shows a coin, which was for sale by the owner of Forum Ancient Coins.

This is not my coin.

https://www.forumancientcoins.com/board/index.php?topic=37054 

My general impression, from reading various forum posts through the past 5 years, and from my imperfect memory, is that an authentic "Tiber patina" happened, when a bronze coin fell into the Tiber River in Italy, or perhaps was buried in the Tiber River, and developed a thin brown patina. Perhaps it's a thin brown patina, similar to the patina of an old Lincoln penny. Perhaps the chemicals in the mud of the Tiber River, resulted in a thin brown patina, and prevented a thick green patina from forming. It's no big deal to me, because I don't know, if it's possible to scientifically analyze the patina of a bronze coin, to determine if the coin was ever in the Tiber River. Also, like you said, the phrase "Tiber patina" may have devolved into a euphemism for a stripped coin with some cabinet patina. Also, it seems that many ancient coin dealers, simply use the phrase "Tiber patina" to describe a thin brown patina, rather than trying to imply that the coin was ever in the Tiber River. What would be a dealer's motivation, to use the phrase "Tiber patina"? Habit? Convention? Imitating other dealers? Trying to sound knowledgeable? Trying to trick a newbie into paying a higher price? Do they know something I don't? I don't know.

I would be slightly interested to read any posts, if anyone has more knowledge about a "Tiber patina", than my word-of-mouth (by reading forum posts) knowledge. Perhaps the phrase "Tiber patina" is simply a bit of word-of-mouth ancient coin collecting lore, sort of like an urban myth. Or, perhaps there is more to it. I don't know.

P.S. : Some of the above coins, seem to have a mixture of yellow and brown colors. However, it seems that, perhaps the yellow color is the bare metal of the coin ("orichalcum", which is perhaps brass, an alloy of copper and zinc, or something like that), rather than a patina. But perhaps the dealers are referring to the parts of the coin with a light brown patina, rather than the yellow parts of the coin. Or, could the yellow parts of the coin, actually be patina, rather than simply bare metal orichalcum?

Edited August 3, 2023 by sand

[Ancient Coin Hunter]

Calling a coin patinated with an especially light or even if it is non-patinated "Tiber Patina" seems a bit disingenuous.

Where is the evidence that the coin was recovered from a river bed?

[Limes]

Like @expat mentions, it appears to address some sort of colouring / toning of the metal. So it's not to apply the term to a coin that's been stripped of its patina or colouring completely. I am however not sure if the 'toning' is the same as a 'patina' as we see it most of the time on other coin: a thicker layer of brown, dark brown, green and so on. I've never held a coin with 'Tiber patina' in hand, so I wouldn't know. My best guess however is that it is a patina; a reaction of the metal of the coin with the soil it was found in, which gives the coin a typical light brown/yellow colour. Perhaps it only happens to bronze coins found in a river(-like) environment, but I wouldnt know that either. Calgarycoin mentions the following however: 

Bronze coins are sometimes seen with a Tiber Patina with this general look. A true Tiber patina forms on bronze coins found in anaerobic water such as the bottom of the Tiber River. Characterized by a natural subdued brassy color with no more than a thin layer of copper oxide, normally with very light pitting evenly over the surface. While this Vespasian sestertius has the general look of Tiber patina the heavy cuprite deposit on the lower right makes me wonder if this is a true Tiber patina or just something similar to it. What a Tiber Patina is not, is a coin simply stripped of a heavier patina to expose a brassy pitted surface.

Two examples after a quick search on acsearch, of which I personally think the colouring (patina?) does the term 'Tiber patina' justice. 

Not my coins, to be clear. 

From the latest Leu auction. The description mentions: "A wonderful, well struck example with a lovely 'Tiber' patina and an exceptional 18th century pedigree. Some corrosion and with a minor surface crack on the obverse, otherwise, good very fine."

The next coin, which happens to be the same type as shown by sand, shows the 'granulated surfaces' maybe? From ROMA XXVIII, which mentions in the description: "Near Mint State; magnificent Tiber patina, with near miraculous preservation of fine detail. One of the finest known examples."