And meanwhile she looked at me with diamond eyes and wanted me to watch, wanted our two gazes also to proceed along serpentine and continuous paths.
-- Italo Calvino, If on a Winter's Night a Traveler, 1981
On wet days, such was the power of habit over him, he rose from his chair at the same hour, and paced his study for the same length of time, pausing now and then to straighten some book in the bookcase, or alter the position of the two brass crucifixes standing upon cairns of serpentine stone upon the mantelpiece.
-- Virginia Woolf, Night and Day, 1919
Serpentine made its way into English in the 1400s from the French serpentin. This term ultimately comes from the Proto-Indo-European word serp, which describes the creeping motion of a snake.