Russian enamel egg - unknown hallmark?

[AG2012]

There is a good reason to use higher standards for enameling.
When heated over 700 degrees C, temperature needed for vitreous enamel, copper in the alloy will oxidize and turn red brownish (the same with gold). Therefore pickling in acid is needed to remove oxidized copper, the procedure not possible when the object is covered with enamel.
The same oxidation happens under damaged (cracked) enamel with development of dark spots that cannot be removed.
Regards

[Dad]

Yes, I know something regarding Russian silver but unfortunately far from all, nobody knows it! Unfortunately there are some writers here that think they know all about Russian silver and try to put other attendants down! Cooperating instead of arguing would be a much better alternative for the readers of this site.

John, you're an old fighter. I did not want to offend you. For so many years, you could be convinced that I present only verified information. So there were circumstances that I have more opportunities to gain knowledge on the topic "Russian silver". But sometimes you are very stupid. In the simplest themes. Really.
Sorry for the "stupid". In Russian it term sounds softer.