A quarter with no errors of that year with the cupronickel layers comprising 1/3 of total weight, the coin's overall composition is therefore 8.33% nickel, 91.67% copper. Its weight is 5.670 grams (0.1823 troy oz, or 0.2000 avoirdupois oz).
The quarter I have weighs 5.5 grams.
It is not magnetic at all. Could it have been a bad planchet that had a foreign material inside the planchet that is harder than the planchet itself.
Absolutely no way that could have happened during or before minting. Any abnormality in the planchet would have been flattened out during striking, the fact that the metal is raised around the hole is further proof that it happened after minting. Simple case of post mint damage.
This is just a theory. The nail that Petespocket55 posted also looks like the nails used for shoeing horses. Farriers also still use a lot of heat at times to custom bend horseshoes. Many have cross hatched heads. If I were to guess, someone might have heated a couple of shoe nails and somehow used a vice to make these impressions. Why? Just to mess with us!