C.N. Douglas, comp. Forty Thousand Quotations: Prose and Poetical. 1917.
Rarity
A lucky man is rarer than a white crow.
Juvenal.
Rarity gives a charm: thus early fruits are most esteemed; thus winter roses obtain a higher price; thus coyness sets off an extravagant mistress; a door ever open attracts no young suitor.
Martial.