Some time after I bought my Menander drachm that I've written about previously, I was able to pick up a lot of three more drachms of the same type fairly cheaply from an English auction house. This auction house had apparently kept them in their vault for a long time. The problem is: these are silver coins--at least they better be!--but they have toned brown like copper. They were this way when I bid on them, so I wasn't shocked by their colour. But I'm still wondering about them. My questions are: why did they go brown? Is this toning, or something different? how could they get that way? should I keep them as they are? or, should I try to treat them in some way so as to remove the brown toning? And if so, wouldn't that destroy some of the value of the coin, as well as damage its surfaces? One of the three is shown below: It weighs 2.42 grams (my scale weighs it differently by about 0.01 every time!). Its diameter matches my first drachm, which I got from CNG. Its thickness seems right, too. If you have any thoughts or insights, please feel free to share them.
Silver reacts with sulfur compounds in the air, as I'm sure you're aware. Silver coins will slowly darken from white to black, eventually. Along the way, the silver may appear brown, blue, etc. But eventually it will darken further. Or at least it should. Some coins don't tone readily or evenly. I have no idea why. You should keep it as it is, I feel. In any case, you cannot stop the toning/tarnishing process easily. Scales are only accurate to the second last digit. So, if your scale measures three digits, you can be sure that your drachm weighs 2.4 grams. The third digit is relatively unreliable.
Thank you, RichardT. I've seen a lot of silver in my life (I worked in a coin shop for seven years), but I can't recall ever seeing silver this brown. Black: very often. Dark grey: yes. Rainbow colours: sometimes. But I can't recall brown. Thanks for the reassurance regarding my scale. Thanks also for weighing in regarding keeping them as they are.
That's a nice coin, Nathan. I agree that it should be left as is. It's an ancient coin, after all, and with the passage of time it will darken, as any respectable ancient coin, bronze or silver, should. I've seen so many coins cleaned so that they are nice and shiny - perhaps nice is not an appropriate word in this context. Regardless, for silver, what is shiny today will be black in the future. It's an unstoppable process, unless the coin is kept in a perfect vacuum. Maybe, in the not-to-distant future, collectors will be able to have their coins stored in outer space, protected from all those nasty gamma and ultraviolet rays, to be forever preserved, unaltered by time. I can't wait.....
Thank you, lordmarcovan! Thank you, robinjojo! I agree that it is a nice coin, though I'm not partial to the brown toning. But I paid the same amount for the three of them that I paid for my similar-grade coin from CNG; I hope to sell them in the future to fund other purchases, though I might keep one, maybe. I like the face on the aegis.
I'm not into ancients but I like them and silver does tone. Let them be. The title of your thread is what caught me honestly. All I could think of was.... ...black gold, Texas tea...