Mother of pearl occupies a peripheral yet suggestive position in the depth-psychology corpus, appearing most decisively in Karl Abraham’s psychoanalytic case literature, where the material substance is read as a condensed symbol bearing multiple unconscious valences. Abraham’s 1927 clinical report of a depressed patient compulsively collecting mother-of-pearl buttons from the street furnishes the richest primary datum: the substance functions as an overdetermined fetish whose appeal condenses oral-erotic libido, feminine symbolism, and the melancholic’s compensatory valorisation of objects. The indexical entries in Abraham’s collected papers enumerate both the symbolism of mother-of-pearl and the symbolism of shells in adjacent categories, situating the term within a constellation that links feminine bodily imagery, depression, and object-cathexis. The broader alchemical and Gnostic literature orbiting this corpus treats pearl symbolism extensively — von Franz reads pearls in the Aurora Consurgens as symbols of the albedo, the anima, and Wisdom; Jonas analyses the Gnostic ‘Hymn of the Pearl’ as a drama of the soul’s exile and retrieval — yet in these works it is the pearl as such, not specifically mother-of-pearl, that carries the symbolic weight. The concordance entry for ‘mother of pearl’ thus sits at the intersection of psychoanalytic object-relations theory and the wider pearl symbolism of alchemy and Gnosticism, with Abraham’s clinical material providing the only passage where the compound term is explicitly theorised.