I like how it kind of borders the portrait of Lincoln. Excuse my ignorance about toning, but will the shiny areas start to dull too in time?
Pretty run of the mill. But attractive nonetheless. I always set ones like this aside, in flips. Yes, if left raw, exposed like that, it will eventually turn brown. You can store it in ways that will help. An Intercept holder, for example. Or in the middle of a roll with other pennies. Lance.
What you are looking at is the remaining luster in protected areas (e.g., along Lincoln and along the rim). The luster in the other less-protected areas (e.g., in the fields) has been lost due to circulation.
That is the remaining mint luster hiding around the rim of Lincoln. Over time it might turn to brown across the whole coin. I would love to have - from pocket change a complete set that looks just like this.