Just a question about this denarius

[MrZun]

So, so far It looks really good and Authentic, Weight is also good, design is great and has flow lines, Nice toning. But It has a grainy Surface, that is normal, right? Is It caused by dirt that was not cleaned?

Edited October 9, 2024 by MrZun

[Salomons Cat]

Looks definitely genuine to me, and I think that this denarius shows a beautiful portrait of Severus Alexander.

The surface also looks good to me, without any graininess. The reddish spots are just some deposits.

[-monolith-]

Porosity is common for these debased coins. It's genuine, it even has die rust which is very difficult to fake.  

[MrZun]

I Just won the Coin in a auction!

[Kali]

The coin is fine and many ancient coins have those kind of surfaces.

[CPK]

2 hours ago, MrZun said:

I Just won the Coin in a auction!

Congrats! It's a beauty!

[Octavius]

Definitely genuine and really nice portrait of Severus Alexander.

[Gallienus]

I think the graininess on the back is simply a characteristic of the metal.  Perhaps rust on the reverse die is my guess. Doesn't appear to be corrosion.  The obverse appears typical and the brown spots don't hurt anything.  Severus Alex was a decent emperor too: he restored the coinage which is why he made denarii and not debased or otherwise antoninanni.  

 

You could get one with better fields or a fully ms one, but you could also pay a lot more.

I've got a decent denarius of Elagalabus possibly w/ cleaner surfaces but it's not photographed.  

Edited October 14, 2024 by Gallienus

[Salomons Cat]

I wonder why die rust is mentioned so often here, @-monolith- and @Gallienus. I don’t believe the ancient Romans used iron dies, so die rust seems unlikely. This has been discussed here. Also, I do not see porosity. The reverse is just from a slightly used die. But please correct me if I’m mistaken.

@MrZun: Congratulations! That’s a very attractive coin

[Gallienus]

20 hours ago, Salomons Cat said:

I wonder why die rust is mentioned so often here, @-monolith- and @Gallienus. I don’t believe the ancient Romans used iron dies, so die rust seems unlikely.

@MrZun

That's a good piece of info. I've just seen the term generally applied so I used it. It does appear that mint-issued dies in ancient times were bronze.

While it's still possible for bronze to corrode, I have another theory. Maybe these coins were originally cast planchlets and then put into a furnace to anneal & soften them. Then if some were insufficiently annealed, they'd have traces of the original porosity from the casting.  That's why you don't find the porosity on the high points.

It doesn't appear to be metal loss from the coin due to corrosion. 

[mr. wiggles]

Interesting thought.

Could it also be that this was struck from one of the last planchetes from a batch. It would have sat the longest on a furnace open to the air and the surface could have oxidized during this time. The surface roughness would then be due to light surface oxidation at the time it was struck which was then lost over time leaving the slightly rough surface behind. 

[Ancient Coin Hunter]

Nice coin and congrats on the pick-up. I am 99.9% sure it's genuine.

[-monolith-]

On 10/14/2024 at 5:04 PM, Salomons Cat said:

I wonder why die rust is mentioned so often here, @-monolith- and @Gallienus. I don’t believe the ancient Romans used iron dies, so die rust seems unlikely. This has been discussed here. Also, I do not see porosity. The reverse is just from a slightly used die. But please correct me if I’m mistaken.

@MrZun: Congratulations! That’s a very attractive coin

Both hardened bronze and iron dies were used to make Greek and Roman coins [1-3]. Die rust is fairly common on a variety of gold and silver struck coins which are mentioned and identified by countless auctioneers [4]. Although extremely rare ancient dies made from bronze and iron have been discovered and even sold at recent auctions [5-7]. Porosity (aka crystallization or erosion) is fairly common on silver coins which is better explained in these articles [8-11].

 

[1] https://www2.lawrence.edu/dept/art/BUERGER/ESSAYS/PRODUCTION6.HTML#:~:text=Although iron is harder than,A.D. iron die is preserved.

[2] https://www.thecollector.com/ancient-roman-coins-how-were-they-made/

[3] https://coinweek.com/coinweek-ancient-coins-series-ancient-coins-made/#:~:text= CoinWeek Ancient Coins Series%3A How Ancient Coins,the strangest episodes in the history... More

[4] https://www.acsearch.info/search.html?term=die+rust&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

[5] https://www.cngcoins.com/Coin.aspx?CoinID=365752

[6] https://www.cngcoins.com/Coin.aspx?CoinID=153091

[7] https://www.cngcoins.com/Coin.aspx?CoinID=365750

[8] https://www.forumancientcoins.com/moonmoth/crystal_coins.html

[9] https://www.ngccoin.com/news/article/4425/

[10] https://coins.ha.com/tutorial/ancient-coin-grading.s

[11] https://www.nature.com/articles/s41598-019-48941-4

[Salomons Cat]

1 hour ago, -monolith- said:

Both hardened bronze and iron dies were used to make Greek and Roman coins [1-3]. Die rust is fairly common on a variety of gold and silver struck coins which are mentioned and identified by countless auctioneers [4]. Although extremely rare ancient dies made from bronze and iron have been discovered and even sold at recent auctions [5-7]. Porosity (aka crystallization or erosion) is fairly common on silver coins which is better explained in these articles [8-11].

 

[1] https://www2.lawrence.edu/dept/art/BUERGER/ESSAYS/PRODUCTION6.HTML#:~:text=Although iron is harder than,A.D. iron die is preserved.

[2] https://www.thecollector.com/ancient-roman-coins-how-were-they-made/

[3] https://coinweek.com/coinweek-ancient-coins-series-ancient-coins-made/#:~:text= CoinWeek Ancient Coins Series%3A How Ancient Coins,the strangest episodes in the history... More

[4] https://www.acsearch.info/search.html?term=die+rust&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

[5] https://www.cngcoins.com/Coin.aspx?CoinID=365752

[6] https://www.cngcoins.com/Coin.aspx?CoinID=153091

[7] https://www.cngcoins.com/Coin.aspx?CoinID=365750

[8] https://www.forumancientcoins.com/moonmoth/crystal_coins.html

[9] https://www.ngccoin.com/news/article/4425/

[10] https://coins.ha.com/tutorial/ancient-coin-grading.s

[11] https://www.nature.com/articles/s41598-019-48941-4

Yes, I’m aware that iron dies have been discovered, but to my knowledge, these were exceptions. If I recall correctly, iron dies were preferred in certain provinces and for some Greek coins, but not for Roman imperial coins.

Your first source says:

Quote

Although iron is harder than bronze, hardened bronze is hard enough to strike even bronze coins, and evidence indicates that bronze containing a relatively high percentage of tin was the preferred material for dies.

Therefore, I’m not convinced that die rust is a common phenomenon on Roman imperial coins. 

Moreover, I don’t see any signs of die rust on the coin shown above.

7 hours ago, mr. wiggles said:

Interesting thought.

Could it also be that this was struck from one of the last planchetes from a batch. It would have sat the longest on a furnace open to the air and the surface could have oxidized during this time. The surface roughness would then be due to light surface oxidation at the time it was struck which was then lost over time leaving the slightly rough surface behind. 

I imagine that the reverse die was already somewhat worn or that the reverse side of the planchet had cooled slightly, making it less malleable.

@Gallienus, I just realised this is very similar to your idea. The way you described it makes sense to me.

Edited October 16, 2024 by Salomons Cat

[-monolith-]

49 minutes ago, Salomons Cat said:

Yes, I’m aware that iron dies have been discovered, but to my knowledge, these were exceptions. If I recall correctly, iron dies were preferred in certain provinces and for some Greek coins, but not for Roman imperial coins.

Your first source says:

Therefore, I’m not convinced that die rust is a common phenomenon on Roman imperial coins. 

Moreover, I don’t see any signs of die rust on the coin shown above.

I imagine that the reverse die was already somewhat worn or that reverse side of the planchet had cooled slightly, making it less malleable.

Both types of metal dies were used for Greek and Roman coins as indicated in the various articles I posted. "Although iron is harder than bronze, hardened bronze is hard enough to strike even bronze coins, and evidence indicates that bronze containing a relatively high percentage of tin was the preferred material for dies. Iron dies were sometimes used, however; marks on some Syracusan coins indicate that they were struck with rusty dies..." There is clear evidence of die rust on the obverse of the OP coin. Die rust, specifically on Roman Imperial coins, is noted more than 275 times in auction postings from dozens of auction houses: 

 https://www.acsearch.info/search.html?term=die+rust+roman+imperial&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

and more than 7500 for both Greek and Roman coins: 

https://www.acsearch.info/search.html?term=die+rust&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

 

[Salomons Cat]

14 minutes ago, -monolith- said:

Die rust, specifically on Roman Imperial coins, is noted more than 275 times in auction postings from dozens of auction houses: 

 https://www.acsearch.info/search.html?term=die+rust+roman+imperial&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

and more than 7500 for both Greek and Roman coins: 

https://www.acsearch.info/search.html?term=die+rust&category=1&lot=&date_from=&date_to=&thesaurus=1&images=1&en=1&de=1&fr=1&it=1&es=1&ot=1&currency=eur&order=1

 

Acsearch has 13'336'384 entries at the moment. 275 mentions doesn’t convince me that it’s common 😄

I assume that something like this is commonly described as die rust. And I don’t see anything like this on the coin in question.

Edited October 16, 2024 by Salomons Cat

[traveler]

2 hours ago, Salomons Cat said:

Acsearch has 13'336'384 entries at the moment. 275 mentions doesn’t convince me that it’s common 😄

I assume that something like this is commonly described as die rust. And I don’t see anything like this on the coin in question.

A struck coin is generally expected to have flat fields, caused by the flat surfaces of the die. The picture which you attached shows a coin with the expected overall flat fields.

Some coins have uneven or grainy fields. This could be due to corrosion if the silver was debased, or the coin be a cast of course. For example a sand cast.

Another possible reason is die rust, which means the die's surfaces were never flat to begin with, resulting in the uneven surfaces being transferred to the coin's fields. 

Edited October 16, 2024 by traveler

[Salomons Cat]

@traveler , the image I attached is of one of the 275 coins on acsearch described as having die rust by Leu. All the coins I’ve seen with this description, including the one attached, exhibit similar characteristics. However, I must admit I’ve only examined around 10-20 examples.

As I understand it, rust makes iron porous, leading to a material deficiency in the die, which results in excess material being deposited on certain parts of the coin where it wasn’t originally intended.

While we cannot definitively say what caused the deficiency in the die without examining it, die rust seems to create a distinct pattern of excess material on the coin, which is usually recognisable. I don’t see that typical pattern on the Severus Alexander denarius above.

If you or @-monolith- notice any specific die rust pattern on this coin that resembles those seen on other coins, such as the ones on acsearch shown by @-monolith-, please point it out, as I’m unable to see it myself.

By the way, as I mentioned, I also don’t see any porosity on the coin. From my understanding, porosity refers to a deficiency in the material of the coin itself, which is essentially the opposite of die rust. This is how I understand the terms “die rust” and “porosity.”

Edited October 16, 2024 by Salomons Cat

[traveler]

Hello,

Here is an old discussion on possible die rust causing uneven surfaces on a coin: https://www.forumancientcoins.com/board/index.php?topic=111258.0

Note the uneven surfaces on the reverse. 

[Gallienus]

13 hours ago, Salomons Cat said:

Yes, I’m aware that iron dies have been discovered, but to my knowledge, these were exceptions. If I recall correctly, iron dies were preferred in certain provinces and for some Greek coins, but not for Roman imperial coins.

@Gallienus, I just realised this is very similar to your idea. The way you described it makes sense to me.

@Salomons Cat Thanks for the comment.  It seems that if one finds two die-linked Roman denarii with similar porosity on both, then one will be able to tell whtehr it was the die or the planchlet.  If it was corrosion on the die, then the 2 die-linked coins would show similar porosity patterns.  If was porosity on the planchlet, before striking, then the patterns would be completely different.

However I'm in a partially evil mood today as I just lost {was outbid} on a superb Roman Provincial AE that I really wanted.  Oh well, c'est la vie.

[Salomons Cat]

39 minutes ago, Gallienus said:

@Salomons Cat Thanks for the comment.  It seems that if one finds two die-linked Roman denarii with similar porosity on both, then one will be able to tell whtehr it was the die or the planchlet.  If it was corrosion on the die, then the 2 die-linked coins would show similar porosity patterns.  If was porosity on the planchlet, before striking, then the patterns would be completely different.

However I'm in a partially evil mood today as I just lost {was outbid} on a superb Roman Provincial AE that I really wanted.  Oh well, c'est la vie.

I think that it is possible to distinguish between porosity and die rust. As written above, I believe that both phenomena are essentially the opposite of each other. With die rust, there is an excess of material on the surface of the coin, while porosity, according to FORVM, is defined as:

Quote

Porosity

A coin surface with tiny "pinprick" pitting, that is many tiny holes formed by corrosion, that appears similar to skin pores.

I’m sorry that you lost that AE, @Gallienus. Recently, I bid on the most beautiful didrachm of young Nero in existence—I absolutely wanted it. During the live auction, I believed I was leading. However, either I missed something, or there was an issue with The Coin Cabinet’s app or a connection problem. Suddenly, the coin hammered well below the estimated value, and someone else won it…

[MrZun]

Hey guys, Sorry for breaking up the talk here, Just showing the Coin that arrived. 🙂

[-monolith-]

It's spectacular, enjoy it.

[Gallienus]

@MrZun

To further enhance your SA denarius, i can suggest the book: Maximinus Thrax by Pearson.  It goes into an excellent background of the times & coinage of the early 3rd century AD. 

It forced me to dig up my sestersius of Severus Alexander & a denarius of Max: both bought before digital photography.