This species of snail is long, narrow and conical. It has a straight spire, and is a mottled purplish to chocolate brown in colour with pale patches. It has distinctive pale to white spiral cords that help to distinguish this species from the closely-related and bright orange Seila crocea. However, it is most alike to Seila atkinsoni, with which it shares the brown colouration and pale cords. However, that species does not feature the white patches of S. marmorata
