6907.21.10 - Unglazed

This HTS category encompasses unglazed ceramic tiles and similar articles intended for use as flags, paving, hearths, or wall coverings. A key defining characteristic for classification within this subheading is a water absorption coefficient by weight not exceeding 0.5%. This stringent low absorption rate typically indicates a dense, non-porous ceramic body, often associated with porcelainized or vitrified tiles.

This subheading is distinguished from its sibling category, "Glazed," by the absence of a glassy, melted coating fused to the surface of the ceramic. While both cover similar forms and applications of ceramic tiling, the presence or absence of a glaze is a fundamental difference in surface treatment and material composition. The "Unglazed" designation specifically identifies products where the ceramic body itself forms the finished surface.

Within this "Unglazed" category, further distinctions are made to refine classification. Subcategories exist to differentiate based on the dimensions of the largest surface area, specifically distinguishing tiles where this area can be enclosed within a square with sides less than 7 cm from "Other" unglazed tiles. This granular approach allows for precise categorization of various tile formats and their intended applications in construction and design.