Classical Numismatics Discussion
  Welcome Guest. Please login or register. 10% Off Store-Wide Sale Until 2 April!!! Explore Our Website And Find Joy In The History, Numismatics, Art, Mythology, And Geography Of Coins!!! Expert Authentication - Accurate Descriptions - Reasonable Prices - Coins From Under $10 To Museum Quality Rarities Welcome Guest. Please login or register. 10% Off Store-Wide Sale Until 2 April!!! Explore Our Website And Find Joy In The History, Numismatics, Art, Mythology, And Geography Of Coins!!! Support Our Efforts To Serve The Classical Numismatics Community - Shop At Forum Ancient Coins

New & Reduced


Author Topic: Spots on siliqua  (Read 3302 times)

0 Members and 1 Guest are viewing this topic.

Offline Johnny M

  • Auxiliary
  • Posts: 1
Spots on siliqua
« on: October 13, 2020, 06:11:41 pm »
Does anyone know what kind of staining this is on a new siliqua I picked up thank you

Offline glebe

  • Caesar
  • ****
  • Posts: 1338
    • Glebe Coins
Re: Spots on siliqua
« Reply #1 on: October 21, 2020, 12:46:09 am »
What exactly do you think this coin is? I don't recognise it as a siliqua - or anything for that matter.
The image needs to be rotated 90 deg. clockwise.

Ross G.

Offline Callimachus

  • Caesar
  • ****
  • Posts: 623
Re: Spots on siliqua
« Reply #2 on: October 21, 2020, 10:16:47 pm »
Shouldn't a siliqua be made of silver?
This coin appears to be copper.

Offline Pekka K

  • Tribunus Plebis Perpetuus
  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 7335
  • ...one coin at a time...
Re: Spots on siliqua
« Reply #3 on: October 22, 2020, 02:16:04 am »

Mintmark reads: AQPS, so says silver.

Pekka K

Offline SC

  • Tribunus Plebis Perpetuus
  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 6068
    • A Handbook of Late Roman Bronze Coin Types 324-395.
Re: Spots on siliqua
« Reply #4 on: October 22, 2020, 09:11:03 am »
It appears to be heavily tarnished silver (hence the black surface).

The lighter spots are either the remains of copper-based adhesions coming from a copper coin or other object once buried near it or differential corrosion from copper impurities in the silver alloy mix.

One would have to see what is "under" those spots.  If the first scenario, they would overlay good quality silver, in the second scenario they would continue down into the surface.

However, to verify this could be semi-destructive.  Gentle probing under microscope would be the way to start.

SC


SC
(Shawn Caza, Ottawa)

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #5 on: October 24, 2020, 06:26:25 pm »
My guess is that it was salvaged (probably ground), and was stuck to another coin. Whether silver or bronze: try 25% CLR solution for a few minutes...

Offline Akropolis

  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 2762
    • Akropolis Ancient Coins
Re: Spots on siliqua
« Reply #6 on: October 24, 2020, 09:39:20 pm »
Note:
This is Pete B
Not PeteB, which is me. 😉

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #7 on: October 25, 2020, 01:08:04 am »
Before and After (after graded ChVF 5/5 and 5/5). Should have graded AU-a lot of original luster was still evident

Offline Mark F

  • Praetorian
  • **
  • Posts: 20
Re: Spots on siliqua
« Reply #8 on: October 25, 2020, 09:05:11 pm »
Pete B,

How did you go from before to after on the Gordian sestertius? Process, tools, etc? Was this your work or someone else?

Mark

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #9 on: October 25, 2020, 09:52:43 pm »
I have it, from a reliable source, just a submersion in a 25% CLR solution. No tooling.

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #10 on: October 25, 2020, 09:55:20 pm »
That type of green "corrosion" is really old, solidified verdigris. If you're lucky, and usually you are, it's on rather than in the coin...

Offline SC

  • Tribunus Plebis Perpetuus
  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 6068
    • A Handbook of Late Roman Bronze Coin Types 324-395.
Re: Spots on siliqua
« Reply #11 on: October 26, 2020, 05:48:50 pm »
That coin was 100% safe as it was.  Just malachite encrustations.

I can see both sides of the decision to clean it.  Both the before and after are attractive coins to me, though I know different people have different views.

Most Gordian III sestertii are in fairly good condition as they did not circulate for very long afterwards.  By contrast, sestertii from the early and mid-second century can be quite worn and when such coins have malachite encrustations they can really hide the limited detail.

The removal of the malachite can be desirable in such situations.

Use of harsh chemicals can be a real crap shoot though.  I am curious about how long the immersion in 25% CLR was.  But in any event, though it turned out well in this case there is no guarantee it always works.

SC


SC
(Shawn Caza, Ottawa)

Offline Meepzorp

  • IMPERATOR
  • Caesar
  • *****
  • Posts: 5127
    • Meepzorp's Ancient Coins
Re: Spots on siliqua
« Reply #12 on: October 26, 2020, 07:55:21 pm »
Hi PB,

Regarding the Gordian sestertius, I think you "ruined" it. In all honesty, I like the "before" photos better.

In my opinion, the only time that anyone should alter the surfaces of a coin is when it has active corrosion (bronze disease). If it doesn't have active BD, you should leave it alone. In your coin's case, it had harmless encrustations that, in my opinion, actually enhanced the surfaces and made it "prettier".

I wish that people would stop messing around with (and "ruining") ancient coins. I don't know when they are going to learn their lessons.

Meepzorp

Offline Meepzorp

  • IMPERATOR
  • Caesar
  • *****
  • Posts: 5127
    • Meepzorp's Ancient Coins
Re: Spots on siliqua
« Reply #13 on: October 26, 2020, 08:20:44 pm »
Hi PB,

By the way, I also feel the same way about antique cars. This is especially true for antique high performance Mustangs, which are my favorite cars. Too many people modify them and turn them into "resto mods". In my opinion, they "ruin" them when they do that. I wish that people would leave them alone and keep them as original as possible.

About the only exception to that would be antique high performance Mustangs built during the "gas crisis years" (1979-1981). Now that those cars are antiques, I understand the need to modify them because they had horrific engines. Those Mustangs came from the factory with either a "sleeved down" 5.0 liter V8 engine (a 4.2 liter engine in a 5.0 liter engine block) that produced only 115 horsepower, or a 2.3 liter 4 cylinder Pinto engine with a turbocharger that was extremely unreliable and had a tendency to "self destruct" when it had very low mileage. Because of world events that were beyond their control, Ford was forced to "ruin" (or "neuter") those cars at the factory when they were brand new. In my opinion, this is the equivalent of bronze disease on an ancient coin.

Meepzorp

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #14 on: October 26, 2020, 11:34:52 pm »
NGC liked it. A lot.

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #15 on: October 26, 2020, 11:49:11 pm »
I posted this on a FaceBook site, but it's worth repeating here: years upon years ago someone bought a fused pair of Caligula Vesta Ases, separated them, carved away anything that wasn't metal from one of them with an Exacto knife, and it was 'nice'. It was brought to a GSNA show where a dealer saw it, hemmed and hawed but bought it. An hour later it was in his case, on velvet all by itself, for $800 with a sign that stated "One of the Finest I've Ever Seen".

Whether you like it or not, there are a lot of nice coins "out there" that need to be conserved; otherwise they can and will waste away. Aesthetics is another matter. I don't know about the green on the Sestertius being Malachite: that particular mineral does not dissolve in CLR as far as I have found

Offline v-drome

  • Caesar
  • ****
  • Posts: 1060
Re: Spots on siliqua
« Reply #16 on: October 27, 2020, 01:05:03 am »
I agree with Meepzorp.  There was no active corrosion on the coin and the fine patina actually protects it (It is still a very nice coin).  Also, with regard to the siliqua at the top of this post, to me it looks like a thick layer of horn silver which, if stripped, will leave practically nothing of the detail of the coin.

Offline Meepzorp

  • IMPERATOR
  • Caesar
  • *****
  • Posts: 5127
    • Meepzorp's Ancient Coins
Re: Spots on siliqua
« Reply #17 on: October 27, 2020, 04:36:41 am »
Whether you like it or not, there are a lot of nice coins "out there" that need to be conserved...

Hi PB,

There is a huge difference between "conserving" a coin and "ruining" a coin. Those are 2 vastly different things.

Regarding this particular coin, there was nothing to "conserve". It had a stable patina with harmless encrustations that actually enhanced the beauty of the surfaces. There was no active corrosion (BD).

Meepzorp

Offline Meepzorp

  • IMPERATOR
  • Caesar
  • *****
  • Posts: 5127
    • Meepzorp's Ancient Coins
Re: Spots on siliqua
« Reply #18 on: October 27, 2020, 04:41:03 am »
...otherwise they can and will waste away

Hi PB,

Nothing can be further from the truth. In fact, the exact opposite of that is true.

By stripping the patina, you made the coin significantly more susceptible to bronze disease in the future.

Meepzorp

Offline Meepzorp

  • IMPERATOR
  • Caesar
  • *****
  • Posts: 5127
    • Meepzorp's Ancient Coins
Re: Spots on siliqua
« Reply #19 on: October 27, 2020, 04:46:10 am »
NGC liked it. A lot.

Hi PB,

When it comes to ancient coins, NGC really isn't an authority, nor are they very knowledgeable.

Did NGC know that the patina was stripped?

Did NGC know that the coin was actually prettier until very recently, when someone decided to "conserve" (ruin) it?

Meepzorp

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #20 on: October 27, 2020, 04:57:13 am »
To Each Their Own... some entertaining comments here! BTW: the Gord sest. brought in over $100 more devoid of the verdigris

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #21 on: October 27, 2020, 04:59:08 am »
a coin regraded as ChVF 5/5 and 5/5 probably isn't a "ruined" coin

Offline glebe

  • Caesar
  • ****
  • Posts: 1338
    • Glebe Coins
Re: Spots on siliqua
« Reply #22 on: October 27, 2020, 06:42:14 am »
So stick the siliqua into 25% CLR and see what happens. It's hardly going to make it worse than it is.

Ross g.

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #23 on: October 27, 2020, 10:35:25 am »
Yes, and I wouldn't worry about "Horn Silver" being a problem

Offline Pete B

  • Consul
  • ***
  • Posts: 139
Re: Spots on siliqua
« Reply #24 on: October 27, 2020, 02:11:06 pm »
Annnnd, for those who wonder about NGC's efficacy concerning Ancient coins, may I remind everyone that they have their company-founded Numismatic Conservation Services department?

For myself, I would prefer a Perfect 86 ct Diamond cut from a 128 ct raw stone

 

All coins are guaranteed for eternity