My apologies as I'm sure there's a numismatic term for this, but I'm new to ancient coin collecting and am intrigued by some white "stuff" I found on a recent purchase. Here it can clearly be seen around Zeus on the reverse. It's also in Herakles' ear. Alexander III posthumous tetradrachm 323-320 BCE. Amphipolis. Issued by Antipater. Price 112; 17.06g, 26mm, 3h. Purchased from Roma Numismatics Did someone 2300 years ago have a thing for Oreos? Is this centuries of earwax? I love the coin and am just wondering what this stuff is. Thank you in advance for the replies. So much to learn...
My guess is someone rubbed a coating of wax over the coin at some point and it's turned white where the remnants of the wax is thicker. Does it look like a waxy deposit under a magnifying glass? Be careful trying to rub it off though. Even a Q-tip can cause damage if rubbed across the surface of a silver coin.
I would first try an water soak to see if it is some sort of salt, then follow up with acetone and then xylene. If that doesn't do it, let us know
What a beautiful tetradrachm I'd read that Zeus had a cocaine habit, but jeez, he's rubbed it all over his body
I don't know what the deposits are. But, if it is modern and easy to remove I think Roma or the consignor would have done so before selling. I have a coin with a similar problem: Because of the granulation on the outside, I thought my coin might be crystallized on the inside. Crystallized coins can lose weight over time. (I have a tetradrachm from Alexandria that has lost about 50% of its weight in the process). I speculated that perhaps the deposits on my coin might have leached out as a result of the crystallization process, and not have come from the outside. Of course, that is just wild speculation. And coming from someone who knows zilch about chemistry... I hope someone more knowledgeable can chime in.
Perhaps mine has the IONA CRYSTALLIZED DESERT PATINA... Iona-Miletos AR Obol Late6thC crystallized lion laying LEFT facing RIGHT
Did you try using a toothpick to check if you can remove it? I had a similar waxy deposit which was quite easy to remove this way, see the before/after photos I attach. If you can't move it with the toothpick better leave it alone.
This post brings us to the verge of 'forensic numismatics'. I love technical numismatics or all kinds (except, possibly, cleaning) because it allows me to take photos that are not just passport/drivers license grade. Being around for a couple millennia and being subjected to scientist/collector abuse for a couple centuries has made for some interesting things on our coins if we look closely enough. In this case, right or wrong, I tend to blame a waxy material applied to make the coin look better but using the theory that if a 'dab' would 'do' a ton would do better. The obvious culprit here is RenWax which really is a thing commonly overdone but it could as well be Johnson's floor wax. Nose Grease was a common material film era photo lab techs applied to negatives with minor base scratches and works on coins in some cases. Earwax? I had not thought of that one. Baking soda used to polish the coin to a glitter? Possible. kirispupis, since you already have a lot of camera gear and the inclination to use it on coins, I would suggest you get a stereoscopic microscope with the added capability of adapting a camera via a third eye-tube. Mine does not have this camera port so I just use a stack of about 100mm worth of extension tubes on a 100mm lens. While the coin looks clean in a 'normal' photo, this 1 1/2 assaria of Philip II from Tomis shows waxy flakes (possibly skin cells) and salts adhered by grime. There are several pieces of red flocking that came from trays that once housed my collection and just plain old dust. Cleaning a coin well enough to take a photo at this scale (these are two full frame shots combined and reduced to fit here) is no easy task. The stereo microscope would help but it is easier to use a spot healing brush in postprocessing. This sample has not been 'decluttered' yet but is about as clean as I usually get a coin before shooting. I started working on a set of what I considered to be interesting coins with centration dimples (there are several varieties of these which I find fascinating). Whether I will follow through that to completion remains to be seen.
Ignoramus Maximus, post: 7746759, member: 104741"]I don't know what the deposits are. But, if it is modern and easy to remove I think Roma or the consignor would have done so before selling." Agree, the white on your coin is some sort of mineralization. I forgot to say IMO. BTW, much of what I post is an opinion and I should not need to remind the members who say I'm a KIA. View attachment 1326190 View attachment 1326189 PS If Renwax turned white, there would be millions of examples like the OP's coin.
Thank you for all the replies. In retrospect, I should have probably asked this before I put it in my album, as access is now difficult. For every coin, I place it in a coin holder, then tape the holder onto a page I write about the coin. That page then goes into a plastic sleeve. This provides context on the coin and makes it impossible without destroying the page to get at the coin, which is important because most of my relatives will handle my coins even when I tell them not to. It sounds like this is either something placed by a previous owner or a natural mineral deposit. I used a magnifying glass to take a closer look, and this is what is seems: - Whatever the stuff is, I don't believe it's natural. It doesn't flow naturally with the coin. - It doesn't look like wax, but more like a paste. Hooking up a stereoscopic microscope as @dougsmit recommends is a good idea, but with both more coins and a Canon R3 on the way, I may undergo severe bodily harm if I bring up that idea (which I've looked into before). I may contact Roma to see if they have an idea. Again, I'm happy with the coin and have no intentions to return it. I'm just curious what the stuff is.
So if I get this well, you don't want to take the coin out because you will destroy a page you wrote about the coin and you use this page as tamper proof to prevent your relatives from handling your coins? Why don't you get your coins slabbed then? Or even better put a booby trap in your album eg smth like a tazer?
Below is an example of what I do for each coin. It's not just about protecting the coin, but on providing more of its context and history. I can technically take the coin out. I'll just need to replace the holder and reprint the page (they're all saved for that purpose), but it's still a bit of a pita. In terms of slabs, I don't really believe in them. I've never bought a slabbed coin, but if I do then I'll free it. In terms of the Antipater tet, if I feel positive that I can/should do something about the white paste, I'll open it. To be honest, when I asked the question I thought it must be some mineral or aging artifact. I figured it must be common and was just curious about the science. It never occurred to me that I might be able to remove it, let alone that I should.
Might it be plaster? Making a mold of a coin by direct casting in plaster is a bad idea but maybe someone didn't know that. I don't think your coin is a cast, but sometimes white stuff in the crevices is leftover jewelry investment from the casting process. Again, I'm not saying your coin is cast, just mentioning instances where you might see white stuff on a silver coin.
I would give anything to have a relative who wanted to handle my coins. A low end stereo microscope costs less than the sales tax on an R3 unless you live in a state with no tax. Yes, Leica does make scopes that cost more than a complete RF lens set. That is overkill even for the best coins. I would be interested in what the white stuff turns out to be and what removes it. Acetone strikes me as most likely. I would place the coin under the stereo microscope and probe the stuff with a toothpick. Yes, you can scratch a silver coin but usually it is not the tool (like Q-tip) but dirt imbedded in the tool that scratches but having a light touch helps. My coins are all scratched before I get them. I have no proof ancients.
Respectfully, unpack the coin and probe the white stuff with toothpick, as Doug suggests. Please save us all the speculation.
Thank you everyone for all of your advice! I unpacked the coin, rubbed it with a toothpick, and found that whatever the stuff is, it's coming off. I also took a closer photo with my MP-E 65 (5x), though I should have taken two and stacked them due to the DOF. I also have 10x and 20x lenses that I just remembered I owned, but I unfortunately sold the tube lens for them some time ago (and they need a specialized stand anyways). Here's a closeup of the "stuff." Here's the cleaned coin. Zeus unfortunately still isn't over his cocaine habit, but he's seeking help and getting better.
Nice job! The surfaces under the deposits that you removed seem fine. A soaking in distilled water, or acetone if distilled water is ineffective, should remove the remaining white substance. Gentle use (light pressure) with a clean wood toothpick should quickly complete the process. Just rinse the coin with distilled water and pat it down in a cloth or tissue. On the other hand, you could leave the coin as is, since the remaining deposits are not very evident with magnification - it's you call.