: The monopolist gains from the discrepancy between the socially necessary labor-time embodied in land or conditions that he / she owns and the socially necessary labor-time embodied in land or conditions that confronts those who attempt to enter the monopolist's market.
Marx actually discusses Monopoly pricing in Capital three, section on Rent, chapter on Rent of houses, Rent of Mines, price of Land, in whichhe uses teh example of a Vineyard. Further, he also notes in the Introduction to Section on Rent, that such things as cannot be replaced by labour, such as antiques, have a price not determined by value. IIRC he defines a monopoly price as being where price is determined by desire andd ability to pay, and not value.
I was gonna bring these quotes in, but forgot them, I'll post them in full on monday.
: Monopoly prices, however, do INCREASE exchange-value.
But they do price.