2518 - Dolomite, whether or not calcined or sintered, including dolomite roughly trimmed or merely cut, by sawing or otherwise, into blocks or slabs of a rectangular (including square) shape:

HTS Code 2518 encompasses dolomite, a mineral primarily composed of calcium magnesium carbonate. This classification applies regardless of whether the dolomite has undergone calcination (heating to remove carbon dioxide) or sintering (heating to bond particles). The category also includes dolomite that has been roughly trimmed or simply cut into rectangular or square blocks or slabs, indicating a basic level of processing.

Dolomite, at this level of the HTS, is distinct from other mineral products classified in Chapter 25, such as various types of salt, sulfur, earths, stone, plastering materials, lime, and cement. While it falls under the broader "Ea rths and stone" grouping, HTS 2518 specifically isolates this particular carbonate mineral. It is differentiated from other stones and minerals by its unique chemical composition and associated properties.

Within HTS 2518, two primary subcategories exist to further refine classification based on processing. HTS 2518.10.00.00 covers raw or simply cut dolomite that has not been subjected to calcination or sintering. Conversely, HTS 2518.20.00.00 specifically covers dolomite that has undergone calcination or sintering, a process that alters its chemical and physical properties, often preparing it for specific industrial uses.