Surprisingly, I notice the BU state quarters that I packed away in small envelopes all have a certain tarnish. Sometimes it's purplish, some are bluish and some are rainbow-like. Which metals are causing this? Even my new US cents haven't tarnished this quickly.
Usually it's not the metals that are causin the tone but it's the enviroment that you are exposing it to or where it had been in the past.
They are being kept in the small coin envelopes, mailia in color, with the flap closed. The patina is actually attractive and wipes-off easily with a tissue.
I was told by a coin company that uncirculated statehood quarters will tarnish or tone as a result of not being handled all the time as circulated quarters are. I don't know what would happen if they were in airtites because no air would be allowed in. Might be the only way to keep them from toning.
There you go. It explains everything. Usually coin envelopes in particular the yellow ones do have sulfur which is one of the active compound for toning. Think about it - most metals from ores are not in pure form, usually in forms of sulphides, i.e. iron sulfide, nickel sulfide etc or other forms.
Sulfur and oxygen from the paper (or from the air) generate sulfides and oxides that convert the pure metal on the coin surface. This is the definition of tarnish. Sulfur compounds may be present in elevated concentrations as a pollutant in the air where you live.
Please don't do that---when you wipe it you are leaving hairlines all over that coin from th tissue---more than likely under a 10x you coin would look like sand-paper. Speedy
The 1999 and 2000 quarters in my Dansco album have started to tarnish. They have this even light golden tone to them. Storage until 4 weeks ago: my parents house in VA, up stairs, Climate control set at 68 year round, and their dehumidifier runs 24/7. So, yes, the new quarters are tarnishing, from MY experience. Then again, all the quarters in my albums were taken from coins in circulation.
