Hello gentlemen (and ladies?) !

I've found one interesting piece in my "box" . This is absolutely Choice BU 1 kopek 1828 with a decent crack.
We all know about flan defects on Russian roubles of the first half of XVIII century but I've never seen those on copper coins XIX century. Any ideas ??

Thanks for your time !

This is what Philadelphians would call a "Liberty Kopeck"

Must have used the same copper!

I do not think it is a flan defect. Metal cracks at the time of strikin by dies. Quiet common on 1 kop pieces of 1810 - 1830. Also can be seen on 2 kop of Paul I. Never saw it on 2 kop of 1810 -- 1830.

This is my 1811 with a similar crack:

Thanks guys. Was it a result of the outdated technology? I do not recall such examples after 1830 or so.

We should ask them Does anyone live close to Philly ? Looks like this is the place where nice Russian copper coins can be found

Maybe it's less likely to happen when coins are struck in a collar.

I would say that it is practically impossible to happen if struck in a collar

Practically but not technically, we've seen many flan flaws for later-year coins as well.
By the way, NGC, for example, always has hard time encapsulating coins with this defect. They should create a separate gradation for the technology used

I think it happens when the coin is struck outside of the collar. I do not believe I have seen a coin struck in a collar with such a crack. Collar does not allow metal to expand without control, which is what creates such defects. Can somebody please show a photo of a coin struck in a collar with such a crack?

While more common in coins struck w/o a collar, it can and does happen regardless of collar. At one time I owned a very neat 1853 US large cent that was virtually split in two. There are also significant number of later US coins on cracked planchets including a couple spectacular Morgan Dollars - just seach some of the error sites.

Cause of cracking is inadequately annealed planchets and/or internal defects such as inclusions, laminations, poor alloying, etc.

That's more like it. Thanks for the feedback.