Specks of Green

Discussion in 'Ancient Coins' started by differential, Jun 16, 2021.

  1. differential

    differential Active Member

    There is a Roman Emperor coin from the first century I'm looking at. I've been searching awhile for this and they are a bit hard to find, I think. To me the coin looks beautiful--it's a golden bronze with some brown corrosion and specks of green corrosion. The blend of these gives it a singular appearance. It doesn't look like it's going to obliterate in the next century or so.

    The total effect, to me, is stunning. The coin seems to have a glow about it.

    I know on Early American Coins this much corrosion (to many people)would detract from the coin.

    The coin is from a trusted dealer from whom I've worked with before, and it's guaranteed by their experts, and they'll buy it back anytime if it shows itself to not be authentic.

    BTW I often trust my intuition and judge coins overall, although I'm well aware of how to grade.

    In general, what's your thinking on these two issues when you buy ancient coins? I have six more seven ancient coins, so I am at the start of a learning curve.

    Thanks in advance.
    Marsyas Mike likes this.
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  3. Roman Collector

    Roman Collector Supporter! Supporter

    Post a photo of the coin; it's the only way to render an opinion
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  4. differential

    differential Active Member

    Thanks for the quick response. I'm just asking a general question here that would apply to these issues in general. With very old coins there seems to be much more acceptance of what might be considered flaws or problems on modern coins.
  5. red_spork

    red_spork Triumvir monetalis

    "Corrosion" can mean different things. There are stable coins that won't or haven't changed in decades with photographic evidence(i.e. old catalog photos) and there are those that with active corrosion that will continue corroding over the course of weeks, months or years. If the corrosion is active, this can be a pretty serious issue and in general I try to avoid such coins, but it's not always obvious. If the corrosion is stable, especially if there's evidence that it hasn't changed in several years, it doesn't bother me much if the coin otherwise ticks all the boxes for me.
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  6. Insider

    Insider Talent on loan from...

    Usually GREEN or RED color indicates "active" corrosion.
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  7. hotwheelsearl

    hotwheelsearl Well-Known Member

    I guess unless it’s inert verdigris
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  8. sand

    sand Well-Known Member

    There are many ancient coins, and Byzantine coins, and ancient Chinese coins, with a dark green patina, that are more valuable, because of the dark green patina. Even a medium green patina can be highly desirable. Sometimes a light green color, means that the corrosion is active, but not always. One has to look at the coin, either in a photo, or in hand, to know, if the corrosion is active. If the entire coin is green, then the coin is usually more valuable, than if there are small green spots on the coin, if the 2 coins are otherwise equivalent.
    Last edited: Jun 16, 2021
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  9. Alegandron

    Alegandron "ΤΩΙ ΚΡΑΤΙΣΤΩΙ..." ΜΕΓΑΣ ΑΛΕΞΑΝΔΡΟΣ, June 323 BCE Supporter


    Your avatar states: “Talent on loan from...”. Where?

    No. This is not active, and it is green.

    GALLIENUS with Goober

    RI Gallienus 253-268 CE Ant Milan mint Laetitia S -secunda

    No. This is not active, and it is red.

    KYRENAICA Kyrene Æ25 9.6g 250 BCE Diademed Zeus-Ammon r - K-O-I-N-O-N; Silphium plant; monogram SNG Cop 1278 BMC 16-19

  10. differential

    differential Active Member

    Thanks everyone for all these good thoughts.
  11. ambr0zie

    ambr0zie Dacian Taraboste

    I found this coin very attractive. The green color was a plus after I checked the pictures.
    Apparently other bidders didn't share this opinion - well good for me.

    This one is the first coin on my first album with ancient coins. Not sure if the patina is natural, but I sure like it.

    I also find the toning on this coin very pleasant.
  12. Kentucky

    Kentucky Supporter! Supporter

    The green that you REALLY have to look out for is the flaky stuff. This is fortunate in that if you have a coin you are questioning, it is really easy to give it a few soaks in distilled/deionized water and brush it with a toothbrush, and prodding deeper areas with a sharpened toothpick. If it is bronze disease or equivalent, this should remove a lot of the danger, and then drying it in an oven at 200 degrees or so for a few hours. Got any pictures?
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  13. differential

    differential Active Member

    Ambr0zie and Alegandrom,

    Alegandron, The two coins with red and green that are NOT active give me a good idea of what a coin with stable green and red look like. I think ancient coins with different signs of wear and coloring can be really neat to have.

    Ambr0zie,Now I know what to look for in searching for a unique patina. Coin #1 is gorgeous and I'd like to have a coin like that someday.. Coin #2 reminds me a bit of the overall patina on the Statue of Liberty. On the coin it's almost a cameo effect. Neat. That third coin is singular, definitely an eye-catcher.

    I decided not to go for the coin. The green spots looked like they were eating into the bronze.

    BTW--I didn't have permission to use the photo so I didn't put it up. I know it's a pain because you can't see what I'm talking about but I try to respect photos others took unless I definitely have permission or it is clear they can be copied and posted.

    Never would have learned all of this about patina vs. corrosion/damage in books--I have been reading alot in the past few months, haven't come across this at all. I'm going to make sure I really look at future coins under higher magnification. I can't imagine how many thousands or tens of thousands hours of experience underlays the responses to my question. This is a great site and the members make it top-notch.

    A toast to everyone who helped me. May you sip on something as satisfying as the nectar of the gods. An ambrosial evening to all. b.
    ambr0zie, Alegandron and sand like this.
  14. Insider

    Insider Talent on loan from...

    Alegandron, posted:FAIL...

    Your avatar states: “Talent on loan from...”. Where?

    No. This is not active, and it is green.

    No. This is not active, and it is red.

  15. Insider

    Insider Talent on loan from...

    I should have been more specific. I was not referring to inactive (stable) patinas. Your red coin is a good example. I'll post images of ACTIVE RED corrosion on one of my ancients tomorrow or the next day (for sure when I dig them out). IMO, the bright green on the coin you posted is actually ACTIVE.

    One other thing to consider...TIME. Something you believe is INACTIVE may turn out to be ACTIVE by your great grand children after what you thought doesn't matter. :D

    PS Because of that time element, HARDLY ANY METAL looks to be actively corroding - even ones having powder-like corrosion products.
    Last edited: Jun 16, 2021
  16. Alegandron

    Alegandron "ΤΩΙ ΚΡΑΤΙΣΤΩΙ..." ΜΕΓΑΣ ΑΛΕΞΑΝΔΡΟΣ, June 323 BCE Supporter

    And, yes, the Sun will blink out… someday.
  17. Insider

    Insider Talent on loan from...

    Alegandron, posted: "And, yes, the Sun will blink out… someday."

    I'm glad to see you agree. There is tons of published information about the corrosion of metal. Much of it can be applied to ancient coins.

    Until I get my ACTIVLY corroding ancient imaged...

    Active Red corrosion spots on Bronze Lincoln cent:

  18. Marsyas Mike

    Marsyas Mike Well-Known Member

    Colors found on ancients is one of my favorite aspects of collecting, and I agree with what you say - stunning.

    I'm a bottom-feeder with little interest in grades per se - if I like how it looks, that's good enough for me. Below is a selection of low-grade sestertii from Antoninus Pius (138-161 A.D.). Grades are low, but I sure like the colors:

    Antoninus Pius - Sest INDVLGENTIA Serbia Lot Jan 2020 (0).jpg Antoninus Pius - Sest Libert June 2018 (0).jpg Antoninus Pius - Sest Libertas  NC lot Jun 2020 (0).jpg Antoninus Pius - Sest SALVS ex-Littltn Jun 2019 (0).jpg Antoninus Pius - Sest. Aequitas Feb 2020 (0b).jpg Antoninus Pius - Sest. Caesar PAX Aug 2019 (0).jpg Antoninus Pius - Sest. Caesar PIETAS July 2020 (0).jpg Antoninus Pius - Sest. Salus std. Feb 2021 (0A).jpg Antoninus Pius - Sest. Salus std. Nov 2020 (0a).jpg Antoninus Pius - Sest. Securitas July 2017 (0).jpg
  19. differential

    differential Active Member

    Gosh, thanks for reading this thread and for the beautiful coins. I wouldn't consider any of these coins as being in the realm of "bottom feeders." Time has left its mark on them. And like each of us, they are not what they were in their heyday. Perhaps a reminder to enjoy each day and every coin or photo that comes into our life each day?
    Roman Collector likes this.
  20. differential

    differential Active Member

    To further our discussion:

    Here are some of the top scholarly articles on Bronze Disease, as noted by scholar.google. com. (This source is for academic/scholarly/articles, the importance of each as evaluated through the number of peer-reviewed scholarly publications in fields as diverse as medicine to metallurgy.) I'm not sure one can access the entire article below, but it's a start. I've attached a screen shot of the page from scholar.google.com showing how to make a search and the information about how the scholarly article can be accessed.

    Of particular interest is the third citation, which indicates "it does appear that the work of Mond and Cuboni, whose experimental studies done in the late 19th Century, provided a scientific basis for the bacterial infection theory..."

    Perhaps we might review articles such as this and make postings on them? One of the great things about this hobby, at least to me, is about how one thing can lead to another. Again, thanks to all who have made me more interested in this topic.





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