Anyone Else's Dimes Turning Brown?

Appreciate the knowledge and lingo - thanks!

Yes almost certainly a ground find. Always nice to get a dime mixed in with the cents!

Not much doubt!

I agree with the others it did not come out of a roll from the mint in that way. The alloy used for nickels and the outer clad layers on dimes, quarters, and halves are susceptible to environmental damage also resulting in a darker appearance when they are exposed. Unless you are getting them from mint bags or rolls it would be hard to know exactly what its been exposed to during its circulation. The roll you have is clearly not a direct from mint roll.

The coins can also develop toning. Here are some of the things I've read that can cause a coin to tone dark or can cause a coin to turn a variety of colors, from deep grey or black to mottled or speckled. There are a few cases where it happens at the mint like an uncirculated nickel black beauty.

Experimentation with acid, or just normal corrosion
Burial in the ground
Being tossed in a water fountain
Exposure to intense heat, or very cold temperatures
Storage in a paper envelope, PVC plastic, or open-air case
Contact with caustic chemicals or fumes, such as sulfur or gas
Sitting in a warm and humid environment for long periods of time
Placed in old fashioned coin folders or albums can also cause toning, potentially attractive, with colors ranging from light blues and pinks even to rainbow colors.