What Causes This Coloration On Old Pennies?

Dipping a coin, which involves use of one of many acids, leaves the coin's surface photoreactive and very prone to this kind of toning. If the coin that's been dipped hasn't soaked long enough in an alkaline rinse (baking soda and water) to neutralize the acid, it will almost certainly turn colors. Some people like the effect, some don't. Stick a dipped and improperly rinsed copper (bronze) coin in an old Wayte Raymond or Mehgrig album and in 6 months, it will most likely look like this.

I too suspect that this coin has been dipped.

Chance

Cleaning and artificial lighting will give results as pictured in the ebay listing.

good point on the photography.