Another mint error, horrible green stuff and a lovely portrait!

[leetoone]

The reverse first!

An overstrike and some horrible greenstuff that I am assured is stable 

[leetoone]

And now the obverse which to my eye is beautiful.

Galerius RIC 33 and possibly from the Langtoft hoard.

AD 303 onwards and at 11.4g quite heavy for this issue.

[Jochen]

Indeed, an outstanding bust and worth to share!

[leetoone]

Of course, I forgot to say that it is an unmarked London mint issue 

[Rupert]

1. Nice coin indeed, especially, of course, for the London specialist!
2. Yes, that kind of green should be stable. Will the coin look better when you remove it? I honestly don't know.
3. Interesting that the coin is so heavily double-struck. The minting in the Tetrarchic period was mostly done rather carefully, bad double or off-center strikes seem to be rather scarce to me.

Rupert

[leetoone]

Another example of the same type, not as nice but this one has a definite Langtoft hoard provenance.