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question about what AR coins are like when they enter the market

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Last year, I compiled a set of uncleaned, or as uncleaned as one can find in 2023, coins.  Zurqieh was the main route.

Do most silver coins, like the Sasanians below, have horn silver and have to be cleaned before entering the retail market?  I have some Heraclius hexagrams with ugly horn silver as well.  One hardly ever sees it in vcoins listings of the same denominations.



The bottom one has an attractive golden tone.

Tetradrachms, silver or otherwise, are tough to find in uncleaned condition.  It doesn't show so much in the picture, but the white stuff on the obverse is glossy in person.  It reminds me very much of flowstone, which Gly sometimes encounters in wet mines.  Is this common?






Large silver coins are almost impossible to find in uncleaned state.  This shekel was as close as I could find to a tetradrachm.  Is this more like most uncleaned (although it is a little bit cleaned) silver coins come out of the pot?




And, how does a silver coin manage to get encrusted like this.  Zurqieh has quite a few Sasanians with large (different than this), brighter green adhesions.  It doesn't look like classic bronze disease.  It's not fuzzy and looks pretty solid/thick.  I'm not sure what happened, like if an AEcoin had gotten stuck to it, and didn't come off all the way.

Edited by Nerosmyfavorite68
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  • Nerosmyfavorite68 changed the title to question about what AR coins are like when they enter the market

I can’t speak to the silver, as I am a total nincompoop as to how silver oxidation works. As for the bronze copper, I know for a fact that the cupric-oxide leaches everywhere. In fact, this is a metal detectorist’s bane. 

When I take my metal detector and swing over a bronze target, what I’m actually getting a reading on is the green copper “halo” from all of the years in the ground. It skews the identification of signals. Sometimes stomping on the ground will disturb the signal enough that I can get a better read on what the item is.

If you get an example of multiple metal-type coins in a target, digging usually results in finding that the cupric oxide bonds to whatever copper is also included in that target. All silver coins have at least a small amount of copper in them, so you are going to get a little bit of greening.

in a way, the greening is a sign of authenticity.

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ive seen a number of low grade Athen's Tet's with heavy encrustrations/horned silver on them. Also, from time to time, Denari are very encrusted and i've seen a few good before and afters. i've seen sodium thiosulfate recommended as a solution for cleaning these, however i've nebver done it myself as i only clean cheap bronze.

gotta find a couple cheap silver coins to experiment on, however, like you said, they are rare to find in uncleaned condition. 

My cleaning friends speculate that all when hordes are found, any obvious silver is removed and likely sent to professionals. By the time the "uncleaned coins" reach market, knowledgeable individuals have picked out the good stuff, which is why its uncommon to see.

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Posted (edited)

I've seen owls from the Middle East with green deposits.  I'm sure this occurs elsewhere as well.  The deposits reflect the environment in which the coins have been stored for centuries, even thousands of years.  The green encrustations on silver coins must be the result of other neighboring minerals or objects oxidizing, creating over a long period the buildup of deposits on the coin, with the help of moisture. 

I've actually seen a few instances where this has led to a seller describing a silver coin as a  fourrée, even though the coin is actually silver with green (copper) oxide deposits on parts or all of the coin.  Removal of the green deposits and analysis of the coin (surface condition, any signs of plating breaks, weight, etc) usually resolves the question for or against the fourrée attribution.

Here are three Sassanian drachms and a follis of Maurice Tiberius (separate purchase) that I picked up out of group at the February show in San Jose.  The two drachms to the left had some black deposits, probably horn silver that were relatively easy to remove.  The follis, very nice as-is, is part of the group photo and was not cleaned.


Edited by robinjojo
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Most silver coins come out with something on them, although not always horn silver. I think they're generally easier to clean than bronze because the deposits don't react so much with the fabric of the coin (as in the reactivity series: platinum-gold-silver-copper-lead-tin-iron-zinc-aluminium). So you can clean them more quickly and get more money when you sell them. Horn silver would be the main exception, and it might be that trying to clean it off would leave an ugly surface anyway. Of course, it depends how much silver there actually is in the coin. Antoniniani can have less silver in them than nummi.

This is an uncleaned hoard of silver coins:

They came to market like this:

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It entirely depends on the type of coin, where they were found and age.  You might be surprised to find that they are often nearly as made.  A couple years ago I bought part of a hoard of Tabaristan hemidrachms that looked pretty darned nice, just a small amount of light soil adhering.  Attached are a couple pics, before and after cleaning.



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1 hour ago, Roman Collector said:

Here's a denarius found by a metal detectorist. 


Wow. I'm not familiar with the above coin type. Because of the greenish color, and the seeming thickness of the tone/patina, it looks like a bronze coin, like an as, or dupondius, or sestertius, to me.

Here are seller photos, of my darkest, most toned silver coin, a silver denarius of Trajan. It's basically black, because of the tone. The seller photos aren't very good. The coin looks better, in hand.


Trajan. AR Denarius. Minted 108 AD To 109 AD. Rome Mint. RIC 119. Maximum Diameter 19 mm. Weight 2.86 grams. Obverse : Trajan Bust Facing Right. Reverse : Aequitas Seated Holding Scales And Cornucopia.

Edited by sand
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Most interesting!

I think I'm going to return to the Parthian/Sasanian well.

It's a shame that the Heraclius hexagrams were ineptly cleaned, leaving them scratched up.  I plan to leave any of the uncleaneds as such, as I went to a lot of trouble to find them before they were no longer available.   Cleaning them would only yield another common coin.  Given that I'm a total klutz at cleaning, it will be quite easy to leave them as-is.

I haven't been able to find an uncleaned sestertius, this one being the closest:


This one was sold, 'as found', but I'm not sure if it's faux dirt. 



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Nice victoriatus!  I suppose my Hostilian sestertius can be considered uncleaned.  Perhaps the barest brush-off.  I always envisioned uncleaneds to be more like this. 

In the glory days of uncleaneds, around 2004, coins that I got from dirtyoldcoins would actually be dirt-covered.  I was dumb enough to actually try to clean them (what a pain and a gooey disaster - olive oil).  With my second 2023 chance, I just bought a few to leave as-is.

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