Nacreous pearl light swam faintly about the hem of the lilac darkness; the edges of light and darkness were stitched upon the hills.
-- Thomas Wolfe, Look Homeward, Angel
For the first time in his life Stephen found that he and Rubens were of one mind, particularly as their generous decolletes and their diaphanous gowns showed expanses of that nacreous Rubens flesh that had so puzzled him before.
-- Patrick O'Brian, The nutmeg of consolation
Nacreous is the adjectival form of nacre, a "type of shellfish that yields mother-of-pearl." The word may ultimately derive from the Arabic nakara, "to hollow out," in reference to the shape of the mollusk shell.