Toning Can Occur, Even in Sealed Coin Holders
In reply to a question in “Coin Clinic,” Mr. Giedroyc didn’t answer the question posed to him but also gave misleading and uninformed information – more of an advertisement for PCGS than anything.
If he was informed about testing of toning of coins while in slabs, PCGS or any other for that matter, he would know that the slabs are not airtight and that in as little as 24 hours silver and copper coins can turn color. (See Coin World July 8, 1996, Page 79.) This experiment as oversaw by Weimar W. White, chemist and author of Coin Chemistry, (2012, Page 23) give startling details about toning changes from the three grading services.
It is therefore clear that Mr. Giedroyc is misinformed and mislead as so many other collectors are about slabbed coins. In fact, some third party grading services that slab coins will not guarantee some coins. “Because copper coins are so susceptible to damage and deterioration, certain certification services do not guarantee the grades it assigns to them, i.e. color, as it does with coins produced in other metals.” (Scott Travers, “The 10 Greatest Myths of ‘Slabbed’ Coins, Oct. 10, 2009, www.usgoldexpert.com/articles/ the- 10- greatest- myths- of- slabbedcoins.) For those who want to gain fulling understand of this issue, they can refer to a forthcoming article in ErrorScope on coin toning.
Ron Brown Address withheld
Editor’s note: Following is a response from Richard Giedroyc.
The quote from the PCGS website used to answer the question in the May 31 issue of Numismatic News reads: “A method for keeping coins in as close to their original state as possible is to have them graded and encapsulated by PCGS.” The statement “as close to their original state as possible” does not suggest the slab will ensure the coins can’t be impacted by the environment. Further in the statement it reads, “maximum protection.” I fail to see where the use of the word “maximum” is either misleading or guarantees the surface of an encapsulated coin can’t change.