That's an awesome Indian!! Between this one and the 1883 Indian you posted the other day, you darn near have me convinced I need to move to ND! Your soil is like velvet up there
You know, I've been wondering about the same thing - I've been noticing that my Indians just seem to have a fuller, greener patina than the older Wheats that I've dug, in general. In the pic below, all four coins were dug in the same farmer's field, and presumably were in the ground for a similar amount of time. The Wheats are only about 10-15 years newer than the Indians, yet the Indians have a far more prominent green patina despite the coins supposedly having the same composition. Sorry for the thread hijack - but someone smarter than me must have an explanation. Only thing I can think of is what DougF suggested - that although the percentage of copper is the same, the actual copper is used is of different grade?