Wingspan 10-13 mm.
Very similar to the related C. alchimiella, differing in several subtle ways including the yellow blotch on the forewing, which is shorter and less clearly defined in this species. However, to be certain of identification, dissection of genitalia is advised.
The larva mines a leaf of oak (Quercus), beech (Fagus) or sweet chestnut (Castanea sativa).
The adult moths occur in a number of generations, any time between April and November.