I picked up this 1873 with Arrows quarter about six months ago for my type set. The black dot smack in the middle of Lady Liberty's decolletage was there when I bought it and it hasn't gotten any worse since then. So, I was wondering what y'all thought it might be? Note the lighter-colored halo surrounding the dot. For those interested, I have also included photos of the markers that define the die pairing of 3/B.
Looks like a run-of-the-mill "Carbon Spot". I'd part with the coin since I find it too distracting. But I am not into die marriages.
It looks to me to possibly be some debris on the coin and that caused the toning difference around it. Looking at it with a 10x magnifier on an oblique angle might help to establish if it sits proud of the surface of the coin or is the metal of the coin. It is possible that it is a carbon spot. Hard to tell with the pictures. The large different toning spot on the reverse shield and above the eagle wing and on the leg and knee on the obverse, as well as at her right hand finger suggest to me to be that this spot is caused from the past handling of the coin with something getting on it and not from an alloy concern with the metal of the coin. It is still a nice, lightly circulated coin and may have contributed to the AU55 grade.
That mark isn't on mine but that doesn't mean much. I could have a different variety. BTW what's your source determining varieties? Are there sources for determining varieties for all different face values of Seated Liberty coins. I've got a full set (date/mm) of "Arrows at Date" SL's for all face values. Just never considered varieties.
I wonder if someone carefully attempted a removal. Like touched the spot with dip on a q-tip. Attractive coin overall.
It is a spot, which is a pity, since it's otherwise a nice AU coin. I don't think acetone will budge it. If it bothers you, I'd look for another specimen, because it's not going to grow on you as much as it will gnaw at you. It kind of bothers me, but then you drew my attention to it. I don't know that sending it for conservation would do any good.
Probably a carbon spot in the planchet. I don't find it all that obtrusive, but it would bug the heck out of me if it was in the right obv field!!
For LS quarters, it is "The Comprehensive Encyclopedia of United States Liberty Seated Quarters" by Larry Briggs, C1991. As far as I know, there is no single reference work that covers die varieties for all LS issues. Each denomination is the subject of different works by different people at different times. Some are better than others and some are just incomplete like the otherwise excellent work by Clint Cummins on the half dimes.
I appreciate everyone's comments and speculations. I was hoping for a more definitive answer but the general consensus seems to be a carbon spot, followed closely by someone's efforts to clean something off the coin. Unfortunately, there is no PCGS photo to go with the certification, so I cannot tell if the spot was there when PCGS graded it. The spot is really not all that evident or objectionable, to me at any rate. I bought the coin for the type but also for the numerous hub re-punchings and a possible clash between the date and the rock. Thanks again for taking the time and trouble.
