Ceramic building bricks are fired from clay or other ceramic materials, giving them a distinct vitrified or semi-vitrified body, and are classified under ceramic construction goods headings. Concrete masonry units (CMUs) are cement-based and fall under entirely different tariff headings. The material composition — confirmed by the manufacturer's product specification — is the primary classification criterion, not the shape or end use.

The percentage of voids or perforations in a ceramic brick can affect its classification, as some tariff schedules distinguish between solid, perforated, and hollow bricks. Importers should obtain dimensional and void-fraction data from the manufacturer, since a brick exceeding certain void thresholds may shift to a different subheading with a different duty rate.