2517.10.00.20 - Limestone, except pebbles and gravel

This HTS category, 2517.10.00.20, specifically classifies limestone that is broken or crushed, and is commonly used as aggregate for concrete, road construction, or railway ballast. It encompasses various forms of processed limestone, excluding naturally occurring pebbles and gravel. The key defining characteristic is its intended application in construction and infrastructure projects, differentiating it from other materials within heading 2517.

Unlike its sibling category 2517.10.00.15, which covers natural pebbles and gravel regardless of their size or intended use, this category focuses solely on processed limestone. The exclusion of "pebbles and gravel" in its description ensures that only broken, crushed, or otherwise processed forms of limestone for specific aggregate purposes fall under this classification. The subsequent sibling category, 2517.10.00.55, serves as a catch-all for other materials within the broader heading that do not fit the descriptions of pebbles, gravel, or this specific limestone aggregate.

As this node is a leaf node in the HTS structure, there are no further subcategories to introduce. Classification at this level hinges on identifying the material as limestone and its common usage as an aggregate for concrete, road building, or ballast, distinguishing it from natural, unshaped pebbles and gravel.