Got couple of fakes on Ebay and was wondering what type of fakes are these. They both have very smooth surface (too smooth for the genuine coin), edge is done very deep and sharp, there is also a specific smell, like they were just made. One of the sellers says he got it from old 50+ years old collection.

1820 rouble pic

The 1820 looks ok, but cleaned. Maybe that is the smell. Why do you think its fake? Can you post the edge?

Unfortunately there are fakes of that particular type of eagle as well.

This is what I have which weights a mere 18.8 grams opposed to what it is supposed to weight at 20.3g

Is there anything else about this coin which leads you to believe that it is not genuine? Being a little underweight is not necessarily enough by itself...read your Uzdenikov (pp. 546/547, 2nd edition).

I'm at work so do not have my Uzdenikov next to me. As I recall there was an article about copper coins being regularly under or overweight and the mint would have some really light or heavy coins on hand to add to the batch being weighed to compensate. As far as silver and gold, the weights were fairly accurate IMHO. As I understood these coins were weighed individually not like copper.

What I find surprising is that in post reform Ivan the Terrible (IV) coinage, most coins do fall within the specifications, I find that impressive since some weigh like 0.34 grams (polushkas less but I haven't seen too many of them)

Silver and gold coins were spot checked; therefore, it is possible that under- or overweight coins might be missed. The "remedium" for silver roubles weighing normally 20.73 grams was 0.18 gram. While 18.8 grams would be severely underweight, it is possible that it slipped by the spot checks.

I believe this coin... ebay #370020348935
belongs under the category of this topic.

The odd thing is that his guy has many fakes, (his name is "copy maniac") and describes them as such, but this coin is simply described "as-is" etc.

He has some dangerous copies for sale.

I already sent the coin back to the seller and didn't bother taking picture of the edge. It did look genuine on the picture, that's why I bought it.

I'm pretty sure it's a fake, the surface was extremely smooth, the edge was also wrong. It was done the same way as Catherine's rouble.

I have seen this 1772 rouble in the past and it is almost certainly modern. The other
is unknown to me.

RWJ

I personally don't believe that 18.8grams was permissible by the mint. By Uzdenikov, the max tolerance weight for this particular coin is a deviation of 0.18gram of 20.73gram - something that is almost 2 gram off is like 10% off is quite significant. That said, the obverse seems to have signs of casting as well as the seller being painfully honest stating that he didn't think it's genuine either, hence my final verdict of it being a fake. I will post a higher resolution when I get around to it.

But it is possible because not every coin was individually weighed. However, since you have found casting signs, then it probably is fake.