Why are some coins appear to be toned in with a rainbow like color, what causes this to happen, is it natural or artificial effect.
Don't take this the wrong way but that response deserves a COME ON MAN. Coin Chemistry is an advanced text on the subject written by a guy whose opinion of toning is tantamount to the lunatic fringe of the numismatic community. I really feel as if a much simpler response is appropriate to the OP's question. In a nutshell, rainbow toning is the result of oxidation and a phenomenon called the thin film interface. One of the very best explanations of toning can be found on this very forum written by Jason (physicsfan314). Here is the link: What You Need to Know About: The Science of Toning BTW, rainbow toning can be both natural or artificial.
Oxidation causes toning read the link Lehigh gave . It's a touchy subject . W.W. White who wrote Coin Chemistry believes all toning is damage and should be erradicated , guess he just can't appreciate a well toned coin and how rare a rainbow toned coin really is . He'd dip this coin , one of my favorites . rzage
If I ever get the opportunity to meet Weimar White, there is only one question I would like to ask him. "Excuse Mr. White, I purchased your book Coin Chemistry, CAN I GET A REFUND?"
Anyone get the since the Lehigh96 doesn't like coin/tone doctors? I feel you! In the wrong hands like in the other thread it is used to capitalize on the vanity of toned coins to turn a huge profit. In the right hands it can help detect the work of those (what I call armatures!) destroying coins in the name of profit! BTW: The book is nothing more than a collection of articles! So it's not really a book in the sense of having to work at writing it! Toning is certainly a subjective topic, and for me it depends on the coin. To answer the original question; Sulfur AND Both.
REAL OR FAKE??? We know what does it, now it's all about how? Anyone trained can point it out from a mile away, but did you notice how I used a Dansco to add a little legitimacy to the coin? You just have to be careful with tone coins that demand a premium!
True that Kennedy wasn't to obvious - but thats the point I should start a Real or Fake poll similar to the Grading polls LOL...
Wow, thanks for all of the replies that you made, thanks for the info, I dont think I will buy any anytime soon. Too expensive and the risk is higher than I want.