I have my late grandpa’s silver spoon attached to my fridge with a neodymium magnet. What kind of chemical reaction causes that discolouration?

  • 1stQ@feddit.orgOP
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    6 hours ago

    Thanks for the link.

    That just doesn’t explain the reaction between the two metals.

    silver needs hydrogen sulfide to tarnish, although it may tarnish with oxygen over time. It often appears as a dull, gray or black film or coating over metal.

    Somehow the silver got colourful instead of the usual grey.

    • turboSnail@piefed.europe.pub
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      5 hours ago

      I recall reading something about titanium and its color. The thickness of the surface layer determines the color. It’s just nanometers thick, but that means light begins to do weird stuff at that scale. I suspect the same applies to the silver oxide/sulfide/whatever layer on the spoon. If that’s the case, you’re not actually seeing the color of the surface layer. The layer is exactly the right thickness that specific wavelengths of light get reflected back while others don’t.

      Proper physicists can add more details.

    • roofuskit@lemmy.world
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      6 hours ago

      There are multiple examples of the colorful toning in the article I linked. So you appreciated the link, but not enough ot actually look through it.

      • baahb@lemmy.dbzer0.com
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        5 hours ago

        Pictures of tungsten tarnishing aren’t helpful when op is talking about silver. Stating “thank you, that’s the general idea yes, but I was trying to ask more specifically” isn’t an attack on you. You don’t need to defend yourself.

          • baahb@lemmy.dbzer0.com
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            25 minutes ago

            That is a surprisingly not blue tarnish, if its supposed to explain what OP is showing us, if it makes a point, please help me comprehend.

            I do see that the light has mostly obscured a small band of blue so maybe its at a really neat phase of tarnish, but that’s speculation and this photo provides no evidence that is actually the case. Either way, I really dont think the tarnish article goes far to actually explain the blue aside from describing the mechanism.

      • 1stQ@feddit.orgOP
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        5 hours ago

        I read everything. (Even changed to my mother tongue.)
        Didn’t find anything about interactions of different metals. It only said something about interactions of metals and non-metals.