2520.10.00.00 - Gypsum; anhydrite

This HTS classification, 2520.10.00.00, specifically covers natural gypsum and anhydrite in their raw, uncalcined state. Gypsum is a hydrated calcium sulfate mineral, often appearing in crystalline or massive forms. Anhydrite is the anhydrous form of calcium sulfate. These materials are the foundational elements for plaster products but are not yet processed into them. Their classification here is based on their inherent mineral composition and unprocessed nature.

It is crucial to distinguish this category from its sibling, 2520.20.00.00, which covers "Plasters." While both are derived from calcium sulfate, 2520.10.00.00 exclusively pertains to the raw, naturally occurring minerals before any thermal treatment or additives that would transform them into a plastering material. The distinction lies in the degree of processing; this heading denotes the raw mineral, whereas the sibling covers the manufactured product ready for application.

As this is a leaf node within the HTS, there are no further subcategories under 2520.10.00.00. Therefore, the classification focuses solely on the identification and distinction of natural gypsum and anhydrite as distinct from any form of plaster. Classification within this code relies on verifying that the imported or exported material is indeed raw gypsum or anhydrite, not a product that has undergone calcination or been mixed with accelerators or retarders.