Adult Ectoedemia heckfordi moths are minute - they have a wingspan of just 4.8–5.8mm.
The forewings are a dark grey with a dull white band - a fascia - traversing the wing in the middle.
Like many nepticulids, there is a slight iridescence when the moth is viewed under the microscope.
The wing pattern is not dissimilar to other species, but Ectoedemia heckfordi is distinct from all but one species by the ochre-coloured pencil of ‘hairs’ that arise from the base of the hindwing - these are actually elongated scales.
The reproductive organs of the male are distinctive in small aspects of their structure.