I read this phrase in "Queen of Spades" (Russian: "Пиковая дама") by Alexandr Pushkin. I think it means the same as Russian Beauty.

That phrase literally translates to "the Muscovite Venus." It can mean a couple of things, and I'm not sure which is correct. This phrase is found in the story "Queen of Spades," by Russian author Alexander Pushkin. The Muscovite Venus is a female character in this story (a gambler, actually, who plays card games). Venus, of course, is the Roman goddess of love and beauty. Merriam-Webster says that "muscovite" can refer to two things: 1) Someone from the city of Moscow, Russia (very likely, since the author is Russian) 2) Having qualities like the mineral Muscovite, which is a colorless to pale brown glass-like material. Without having read Pushkin's story, I'm not sure which one of those terms is best, since either one could have literary meaning. But, literally and most likely, the term means a beautiful, goddess-like woman from Moscow.