1981 Susan B.

[Jerrell123]

So one is a 1981-D and one is a P.

It's my understanding they were from mint sets?

 Why do they have this rainbow color?

  Thoughts?

   Thank you

 

[British coins]

Thats some nice toning, I dont know much about US coins so cant comment any further. 

[JKK]

From Wiki: "At the close of production, the Treasury encountered a dilemma: the Mint struck a large number of dollars in anticipation of great public demand, resulting in a surplus of 520,000,000 coins in 1981."

Thus, not necessarily all from mint sets. I agree with BC, that's very attractive on the left one. The right one looks a bit dowdier in the photo, could be the light.

The toning occurs based on what comes into close proximity with the coin. Historically the most common culprit is sulfur in older papers and cardboards, including coin rolls. Of course, there are some artificial toning methods as well, but that looks 100% natural to me.

[Jerrell123]

Thank you

 

[Just Bob]

I really like the look of the "D", and I suspect that the other one looks better in hand than it does in the picture.

[Conder101]

The 1981 SBA's WERE all mint set only.  That 520 million figure is probably how many the mint and Fed still had on hand in their vaults of 1979 and 1980 coins at the end of 1981.

As for the toning of the OP coins, it all depends on the environment they were stored in.