Why: In the short story "Darkness" by Andrew Sean Greer:
A pale, polished face with the craquelure of age, that haughty upturned nose, the brightly-colored lips no longer full as a boarding-school teacher's, and all of her gone soft with a little fat, a trick photograph of the womanAnswer: In art, craquelure is the fine pattern of cracks formed on old paintings. Well duh.
The More You Know: It is sometimes used to detect forged art, as craquelure is a hard-to-forge signature of authenticity. The precise pattern of craquelure depends upon where the picture was painted. There appear to be distinct French, Italian, and Dutch "styles" of craquelure.