Wingspan 3-4 mm.
A small species, well distributed and common throughout most of the British Isles.
The larvae create narrow, often angular mines in the leaves of hazel (Corylus avellana) and less commonly, hornbeam (Carpinus betulae). Sometimes there can be several larvae mining the same leaf. The mines can be found in July and in October and November.
The adults have purplish-bronzy wings with a silvery fascia, and darker purple outside the fascia. They fly in May and again during August.