A strike through of any kind leaves an impression in the coin's surface. The feature we are discussing is raised above the surface of the coin.
Therefore, whatever created it (if we posit that this isn't a retained strikethrough) had to be something which impressed itself into the die, creating a void. So we have to study this in "negative" mode, seeking something which would be a positive on a die (or whatever object contributed the shape) and therefore capable of creating an impression into a die when broken off and struck through. That makes it unlikely that an existing coin could be the contributor, as they're much softer than the dies. Note the cud above and left of the feature we're discussing, and think about what shape that broken-off area would have if you studied it as an individual fragment. I suspect that cud might be the culprit.
Denver didn't strike coins for any other country in 1926. Notice the coin appears to have cud above the I in LIBERTY that includes the edge design. That cud means a piece of the die has broken off and fallen away from the die. If that piece fell INTO the die it could have been forced into the obverse die on the next strike and have formed the "clash".
That really helps to narrow things down. Now it's time for some real sleuthing . . . You're right about that being a potential source of the indentation in the obverse die . . . not a clashing of a reverse die, but damage to the obverse die from striking a fragment of itself. While I'm fascinated by this possibility, I'm also not yet convinced. Why, you might ask? Well, I'm from Missouri of course. Okay, humor aside, I have a supportable reason . . . There are several other coins I've seen exhibiting the same rim cud and die cracking, yet they do not display this anomaly. That means the die fragment would have to escape the coining chamber while striking those several coins, and then find its way back into the chamber to be struck into the obverse die before creating the subject coin. Sure, I know . . . anything's possible, but how improbable is that? I guess I've got to seek out more images of this coin to see if I can find a progression that will reveal the sequence of events.
Now, that's interesting. Another question would be why there's no sign of this type of strikethrough on the reverse; have you enough available data to compare reverses as well as obverses? The strikethrough should appear adjacent to the center star and to the viewer's left of it, where those two lines appear on the reverse of your coin. Oh, and if you own this one, get it into acetone.
A strike through generally doesn't leave any signs on the opposite side of the coin. I'm not saying there aren't exceptions, but I haven't seen any. I don't do that Dave, but the next owner might very well do so.
Okay, I need more unbiased eyes than just my own to decide if what I think is really true. I've found photos of a couple of other 1926-D quarters with similar die breaks and cracks, and they've always looked so much alike to me that I assumed they were all necessarily identical. If you've got the time, please have a look at each, and especially the length of the rim cud, and let me know how you think they compare with mine. Are they exactly the same, or do they differ? http://images.pcgs.com/CoinFacts/27153147_36065497_max.jpg http://images.pcgs.com/CoinFacts/11373710_1411664_max.jpg To me, it appears that the rim cud on the second linked coin is smaller than that on mine and on the first linked coin. If that's the case, then if the coins were all struck by the same obverse die, the die break started smaller, and gradually increased in size as more bits broke off. This tells me it is not plausible that a single die chip large enough to transfer the details in question could have come off of the die. Have I lost you yet?
I took a long look and agre ethat they seem to be from the same die. Because I have to ask: are you sure that part is raised and not that the other areas delaminated, making it appear raised? Otherwise, it could just be a strange strike through. I wish we had more specimens to observe.
Yes, self doubt just caused me to look again, and it is most definitely raised. Because this has been questioned more than once, and understandably so, I think I'll try to shoot a convincing photo or two, perhaps tonight.
Yes, but we're positing this as a clash, not a strikethrough; the latter won't end in a positive on the coin. It had to be hammered into the die. The reverses of all three coins now presented are the same die, evidenced by the die crack thru the right-hand star into the O of DOLLAR. Oddly enough, your OP coin appears to be the earliest reverse (from the progression of that crack) and the latest obverse (from the size of the cud). There's a lot of room for interpretation due to differing photography procedure, though, and I'm discounting that appearance as such as you'll see. Obviously all three share the same die pair. I feel your OP coin has circulated; look at the highest line of the (viewer's) left leg of it compared to how the lighting of the PCGS coins show it - the OP coin is noticeably flatter there while the other two show curvature, while seeming of similar strike quality otherwise. We could think the cud on the OP coin has been flattened by circulation into appearing larger than the other two. There is no way to remove the mark on the neck via polishing. Die wear over a number of strikes could, but it's hard to believe sufficient strikes would have elapsed between the OP coin and the other two without any further progression of either visible die deterioration or cracks. This one is kinda cool. Lots to think about.
Agreed, after some more time examining at lunchtime. I can look at the coin in person again to see if there is more reverse die crack than apparent in the photos - that would lend credence to our shared belief that it is a later strike. No question . . . I bought the coin as an XF / AU. Agreed again . . . I'm beginning to think it may legitimately be a significant variety discovery. If so, there are a few members of CT who deserve a share of the credit for their participation in its determination, even if a series expert must be consulted to confirm it.
I found angling the coin enough to show the "Omega" standing proud of its surface a challenging task. Unfortunately, I think this is about the best I can shoot to convince others that these details are raised above the surface of the coin, and not incuse. If nothing else, compare the side of the detail on which the shadow is cast against the same for other known raised details on the coin. Of course, there's nothing like seeing it in person. - Mike
Being familiar with photography, there was never any question in my mind about whether the feature was raised or not. The lighting play proves it.