Russia 1764 MM Catherine the Great 5 Kopecks  C-59.6  XF Overstrike.  Scarce.  The overstrike area is on the left wreath.  To say this coin is a rarity is the understatement.  I have been a collector of Russian coins for over 30 years and never saw but a few of these.  I  have a very large collection of the large 5 kopeks and numerous examples and dates for EM, AM, and KM mints.  But the MM and CM 5 kopeks, I have only a few examples and they were the best I ran across.  I am sure there are others which are better but I never saw them.  And most of the MM and CM 5 kopeks I did see looked like they were run over by a tractor, maybe a couple of times.  The Russians tended to use their dies after they were worn and the coins minted were marginal at best.  NGC prices this coin at $245 in XF.  Obviously, they never went out and tried to find one.  They have always been scarce.