Hello. The 2 variants listed in Numista show the same weight in the “Features” block. The alloys differ only slightly. According to the Krause reference, the KM22.1a coin (referred to as copper-nickel) is 75% Cu and 25% Ni. The Krause reference lists the alloy of the KM22.1 coin (KM22 per Numista) as 90% Cu and 10% Ni. (Nickel-Bronze per Krause). The Numista photos show the color difference well.
Because not all media shows the different colors accurately, I would like to denote the different weights. As seen in the photos, the colors
of the 2 coins do not transfer well. What I think needs to happen, is for the “Features” block(s) to show the appropriate weight(s). TC
I don't think you can/should change the weight on a coin page or even put in in as a comment based on a sample size of one, especially one that's not UNC. Typical modern tolerance of coins is +/- 2% to +/- 4%. You really need a much larger sample size to create a CR.
Not knowing what tolerances the Berlin Mint was working with back then, stating that the Cu/Ni variant weighs slightly less than the Ni/Bronze coin should be adequate - imprecise, but better than nothing. TC
I'm not concerned about the exact weights - scales can differ. And Numista doesn't use specific gravity specs. I just don't think showing identical weights for different coins is appropriate. And the photo color test doesn't fly either - although it appears Numista did go to some lengths to show the difference. TC
The one is 70% copper - 30% nickel. 70/30 Cu/Ni density is 8.94g/cc.
The other one is 90% copper - 10% nickel. 90/10 Cu/Ni density is 8.94g/cc.
If the coins have the same dimensions the weight should be exactly the same. There is no reason they have to have different weights just because the composition is different.
I own two examples of this coin; both are the KM-22.1 variety and are nickel-brass (they have a distinctive yellowish coloration which implies the 90% Cu/10% Ni composition).
I do not have one of the 75% Cu/25% Ni coins for comparison. based USA 5 cent coins (which are also 25% Cu/25% Ni) those coins should have a different color (metallic gray).
Not sure if the above helps much with the central argument of this post, but it does help one get a feel for how much the weight of the KM-22.1 coin varies.
Well now ….. first off, a BIG thank you for your efforts. That weight discrepancy is unusual. I have a cu/ni example (KM22.1a), but don't have a scale with the necessary accuracy. I am still convinced that there is a weight discrepancy between the two types - although minor. If anyone else has an accurate scale and a KM22.1a coin, please weigh it up and let us know what you find. And I still think there should be some weight specification that differentiates the two types - besides color. TC
N#3110 shows 9.87g. N#129712 shows 9.5g. These can be considered nominal specs. Both types are close enough in weight that if you apply anytypical tolerance formula, there will be some overlap - i.e. the heaviest allowable example of N#129712 could actually weigh more than the lightest allowable example of N#3110. Showing different nominal weights for the different alloys makes sense. TC
Once again I agree with you. And once again there has to be real evidence that they are in fact different. Get the evidence that they are statistically significant different weights and I'll create the CR to change it.
Me neither I’m really struggling with it. I’m colour blind i‘m not the best with things like this at the best of times and the weights have confused me further.
KM 22.1a used to be type Circulating commemorative coin and was recently changed to type Pattern. Seems odd that anybody would have a circulated one in their collection.
The example I have (KM22.1a) is a circulated piece. I have seen other coins offered that were also circulated. Krause has circulated grades listed and with a mintage of over 12,000, i believe quite a few would have circulated.
