How many archangels? :)
As I studied your very nice derivation, one thing that kept nagging me was that it did not consider contact area for the instrument probes. It...
Actually, doing it obverse to reverse ain't that simple to model. The probe tip contact area would be very small compared to the face area of the...
Very nice. And if the probes are positioned on the edge, but aren't positioned directly across from each other? In other words, how will...
So, what happens if your probe placement on the edges is off a couple of degrees from being on a diameter chord? Measured resistance should be...
One annoying thing about submitting coins for crossover grading is that if the coin does not cross, you're not told what grade they think it is....
As Doug mentioned, checking physical characteristics of the metal won't distinguish genuine from fake coins cast or struck from the "real stuff"....
I have a few hologram coins from Kazakhstan. They're part of the flora series. I think they do a great job in the mint and like it that the...
Probably the thread should be "Post your government-authorized hologram coins". This would hopefully avoid the huge number of post-mint hologram...
I know Canada, Australia, and Kazakhstan produce hologram coins. I think the proposed thread is a good idea. However, there are private...
Possibly some automated imaging system that they used to have, perhaps part of a security or tracking system. In the receiving room, coin may...
Stumbled across the image linked below of an 1802 half eagle, cert. no. 06630159, on PCGS website. Why would they put such an image on their...
Because the engine wasn't running, the coin would have probably been blown out the turbofan bypass on start-up without causing damage. However,...
Your survey left out a very important source ... auctions. Cal
A more cynical translation is: "Penetrating strike" = holed "Well struck" = can read date, but not mint mark "Sharp Strike" = can read date and...
If you put it under the Christmas tree, you'll see the colors. Cal
Auction catalogers have a tough job at times. They have to please both the consignor and eventual buyer. One way they try to do this is by...
Nope, and therefore, not watertight. Good article in the Jan 2009 Numismatist by Donald Beussink, who had his collection in a safe deposit box in...
Yes, mintage figures should be reliable for gross production of coins made for circulation and their corresponding proofs. There are some coins,...
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