Here is a fairly nice pic of a 2005 Nickel. How can this be weather damage? The coin shows no real corrosion from weathering....so how is this weather damage?
Chemicals in the atmosphere react with metals. That's why copper turns brown eventually. Something reacted with your coin to change its color. There are some coins that have a different color (due to processing mistakes) right from the mint that are considered errors.
I don't know who told you it was "weather" damage, but they probably meant "environmental" or "chemical" damage. Chris
I know this is not the correct terminology because I am still learning but this coin is so pretty in color. When I think environmental damages, I think of very visible wear. Learned something new again today
No one really told me it was weather damage. I just took a newbie guess. Plus some of the coin that I have found while metal detecting have dark coloring from being exposed to the west texas environment. Still learning....
Hang on to the coin. It could be improperly annealed. Can you even see the clad layer? Try soaking it in some acetone. It doesn't look like environmental damage. Here is a picture of an improperly annealed nickel. Kind of looks like yours. http://www.collectorsalliance.com/1959_Nickel_Improperly_Annealed_Black_Beauty_p/16609.htm
Your right wrong choice of words. I tried to come up with something other than the shiny part. Maybe shiny nickel/copper of the coin.
The copper-nickel in a nickel is an alloy - ideally a uniform mix of copper and nickel atoms. If the mix is not quite uniform, over time as the coins surface ages, you get visible effects. The most common of these is in the Lincoln cent (pre 1982 when they were 95% copper) where you see the 'woody' effect (the coin really looks like it has wood grain) - see here: https://www.cointalk.com/threads/got-wood.65353/ Another facet of coin minting you need to be aware of is 'work hardening' - basically as you work a metal object (including striking it with dies to create a coin) the metal crystals heat up and harden. In order to be struck, the metal needs to be softened in what is called annealing. When the blanks are cut out of the sheet of metal, and the upsetting machine creates the initial rim, that causes the metal to harden and so the coin blank is annealed before being struck. If the annealing isn't properly done, copper atoms migrate to the surface of the coin. This makes the surface a higher % of copper (and softer) and the interior more nickel (and harder). This can cause some outlandish effect, see http://www.error-ref.com/improper-annealing/. However, the most common cause of color changes in coins is exposure to something in the environment - usually coins found in the dirt. The colors you see on the surface of a coin are from thin films of oxides and other compounds. As light strikes the surface, it bounces differently from the oxide and the non-oxidized atoms. This is most common in silver coins (and can be amazing to see - http://www.jhonecash.com/research/toning_physics.asp). But it happens in nickels - you see golden shades, purple, even a few magentas. Unfortunately, most exposed nickels get ugly grey. That's what you have here. A coin that was exposed to environmental factors for a while and then found and continued to circulate until you found it. The give away? Look at the reverse, the fresh gash under the right hand and the ding on the top of the E in E Pluribus. See the exposed unaffected metal? See other dings and gashes that happened before the exposure and how they are uniformly grey?
