This study argues that the corpus of 543 Minoan lighting-related artefacts compiled by Bastien Rueff (2020) contains a structural anomaly: the complete absence of shell-based oil lamps. In our view, this zero-presence phenomenon cannot be explained by environmental, technological, or accidental factors. The analysis proposes a cultural–semiotic explanation grounded in domain purity: within the Minoan conceptual system, marine shells belonged to the water domain, while lamps belonged to the fire domain. Their combination would have constituted a violation of elemental order. This interpretation accords with Mary Douglas’s anthropological model of “matter out of place.” Thus, the absence of shell lamps is not a gap in the archaeological record, but a material expression of a coherent symbolic logic that structured the separation of domains in the Aegean Bronze Age.