Posted 09/05/2012 04:33 am
Toning is caused by a chemical reaction between the metal on the coin's surface and the environment - by "environment" I mean the atmosphere and whatever else may have come into contact with the coin (eg. water, greasy hands, spilled beer on the bar counter, etc.).
"Coloured" toning is generated by the thin film effect, the same natural phenomenon that imparts rainbow colours to oil slicks and soap bubbles. In other words, the coin's oxidation layer is very thin.
If left exposed to the same environment that created the toning, the colours will gradually change, eventually becoming so thick that the colour changes to black.
"Coloured" toning is generated by the thin film effect, the same natural phenomenon that imparts rainbow colours to oil slicks and soap bubbles. In other words, the coin's oxidation layer is very thin.
If left exposed to the same environment that created the toning, the colours will gradually change, eventually becoming so thick that the colour changes to black.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
