It's a beautiful coin. I have seen many coins from 54-S and 55-S that have streaky colors like this. They are usually green striped, with bright mint red behind. I suspect this coin had green stripes that darkened to brown as it aged. OR maybe the green stripes toned slower, and the mint red parts darkened to brown? Hard to say what is stripes and what is background. I've always wondered about the chemistry of these nice toned coins, ie what is chemically different between the stripes and the background.
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