2529.30.00 - Leucite; nepheline and nepheline syenite

This HTS category, 2529.30.00, specifically covers leucite, nepheline, and nepheline syenite. These are naturally occurring silicate minerals, distinct from other materials classified within Chapter 25. Leucite is a tectosilicate mineral and a member of the feldspathoid group, typically found in extrusive volcanic rocks. Nepheline, also a feldspathoid, and nepheline syenite, an intrusive igneous rock rich in nepheline and alkali feldspar, are characterized by their feldspar-like appearance and composition but lack the structure of true feldspars.

Distinguishing this category from its siblings, 2529.10.00.00 (Feldspar) and the Fluorspar category, is crucial for accurate classification. While all are mineral products within the same chapter, their chemical and geological compositions differ significantly. Feldspar, also a silicate mineral, has a distinct crystalline structure. Fluorspar, conversely, is calcium fluoride and belongs to a completely different mineral class. Therefore, the focus here is on the specific mineralogical and geological makeup of leucite, nepheline, and nepheline syenite.

Within this classification, further subcategories exist to refine the classification. The subcategory 2529.30.00.10 is designated for nepheline syenite, recognizing its common commercial importance as a distinct material. The residual category, 2529.30.00.50, "Other," serves to capture any remaining materials that fall under the broader definition of leucite, nepheline, or nepheline syenite but are not specifically categorized as nepheline syenite.