Look at it this way - every one that gets treated that way means there is one fewer natural out there. Therefore, yours are worth more!
Neither do I. I don't have a clue as to how that could happen naturally. Especially since there isn't a spec of toning on the reverse.
Notice the color bands go ROYGBIV surrounding the shapes. Decreased amount of heat I'd say. A sophisticated lasermight simulate this??
First off, that seller has a propensity for selling wildly toned coins. I am quite surprised the coin is in a PCGS slab as PCGS tends to be colorphobic. As to the toning, in my forty plus years of looking at Morgan dollars, I would call this one artificially toned. If so. then how is it in a PCGS slab? I cann't answer that. I am however, highly suspicious of this coin. I would pass on this coin and never look back.
This seller was also selling the infamous Silver Eagle that PCI had graded MS-68 with a Questionable Color designation. The Silver Eagle ended up in a PCGS MS-69 holder.
If this coin hasn't been altered in some way then I'll eat my shorts. So to speak. I never wear any shorts while I'm on the computer, but you get my meaning.
Only a 'coin doctor' can answer your question. I don't know how the coin is artificially toned, but I believe the coin is not naturally toned. PCGS should be held accountable and someone from PCGS should explain how this coin managed to get slabbed by their company. Someone should also ask the seller how he or she manages to find so many 'wildly' toned coins?
wow It appears to be the folded end of a paper wrapper / roll end toning. What would be interesting would to see the reeding on the edge. I stay away from most toning unles slabbed by NGC or PCGS, and yes, have noticed an abundance of these wild tone rainbows. Hmmmm, hard to say other than I would hate to buy a bunch of these at the premiums they bring only to have the trick discovered at a later date and the price bottom drops out.