Looks like something (not sure what) was spilled on it at some point and everything below the high wear spots just retained that color, I don't think that blueish tint is ever going to come out of the low spots. BTW, your pictures seem to be a little clearer through the loupe so keep using that
Just toning due to whatever came in contact with the copper. Copper is a metal that tones many colors. It all depends on what it came in contact with. I collect rocks and I have several pieces of raw copper. Along with the so called, copper color, I have samples of blue, orange, yellow and red copper to mention a few. Very interesting metal.
There could be some residue of something on there, but that just looks like toning to me. I don't find it all that bad looking.
I agree its just blue. Copper rarely can tone blue, I have seen coins coming from metal detecting come out of the ground pure blue. Blue is actually a very rare and desired color on ancient coins. I love finding one, but lots of competition and high prices.
I think that copper sulfate is blueish green, which could be the result of a somewhat diluted acid. It may have been the result of being buried in some slightly acidic soil, or someone tried to clean it with lemon juice, or a hundred other things found around the house. Just my opinion . . .
Of course sir. Copper is easy to become blue under heat. I bring up ancient coins since there is documentation of them being recovered blue, and its a deep, saturated blue to the core which could not easily be faked, so therefore proves it CAN happen naturally over time. Given this is so new, it would not be a deep color, just surface toning.
