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    2528.00.00

    Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight

    HTS code 2528.00.00 covers natural borates and concentrates, including boric acid with specific purity levels. Use this code for classifying these mineral products, noting they generally enter the U.S. with free duty, as defined within Chapter 25's mineral product classifications.

    Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight

    Detailed information for HTS Code 2528.00.00

    This code falls within Chapter 25 of the Harmonized Tariff Schedule, which covers mineral products. Specifically, 2528.00.00 covers natural borates and concentrates, whether or not calcined, excluding those separated from natural brine and boric acid exceeding 85% H3BO3. Subdivisions further categorize these materials into natural sodium borates, natural calcium borates, and all other natural borates, so choose the suffix that best reflects the specific type of borate being reported. Reporting is done in kilograms, and the correct statistical suffix should be selected to indicate the precise composition of the natural borate material.

    ChapterChapter 25 - Salt; sulfur; earths and stone; plastering materials, lime and cement
    SectionSection V - Mineral Products

    Duty snapshot

    Quick reference for the duty outcomes tied to this HTS line.

    General Duty

    Free

    Standard trade partners (NTR)

    Special Duty

    N/A

    Eligible FTA or preference programs

    The general duty rate for HTS code 2528.00.00 and its subdivisions (2528.00.00.05, 2528.00.00.10, and 2528.00.00.50) is free, meaning no duty is assessed on imports meeting the code's description. A special rate is not specified, but eligibility for preferential trade programs, such as Free Trade Agreements (FTAs), may apply, potentially reducing or eliminating duties further, contingent on meeting the rules of origin and other FTA requirements. All reported quantities must be in kilograms (kg).

    Rate of Duty (Column 2): Free

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    Code subdivisions

    2528.00.00.05

    Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Natural sodium borates and concentrates thereof (whether or not calcined)

    2528.00.00.10

    Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Natural calcium borates

    2528.00.00.50

    Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Other

    Chapter & section notes

    Chapter notes

    Harmonized Tariff Schedule of the United States Revision 29 (2025) Annotated for Statistical Reporting Purposes CHAPTER 25 SALT; SULFUR; EARTHS AND STONE; PLASTERING MATERIALS, LIME AND CEMENT V 25-1 Notes 1. Except where their context or note 4 to this chapter otherwise requires, the headings of this chapter cover only products which are in the crude state or which have been washed (even with chemical substances eliminating the impurities without changing the structure of the product), crushed, ground, powdered, levigated, sifted, screened, concentrated by flotation, magnetic separation or other mechanical or physical processes (except crystallization), but not products which have been roasted, calcined, obtained by mixing or subjected to processing beyond that mentioned in each heading. The products of this chapter may contain an added anti-dusting agent, provided that such addition does not render the product particularly suitable for a specific use rather than for general use. 2. This chapter does not cover: (a) Sublimed sulfur, precipitated sulfur or colloidal sulfur (heading 2802); (b) Earth colors containing 70 percent or more by weight of combined iron evaluated as FeO (heading 282l); 2 3 (c) Medicaments or other products of chapter 30; (d) Perfumery, cosmetic or toilet preparations (chapter 33); (e) Dolomite ramming mix (heading 3816); (f) Setts, curbstones or flagstones (heading 6801); mosaic cubes and the like (heading 6802); roofing, facing or damp course slates (heading 6803); (g) Precious or semiprecious stones (heading 7102 or 7103); (h) Cultured crystals (other than optical elements) weighing not less than 2.5 g each, of sodium chloride or of magnesium oxide, of heading 3824; optical elements of sodium chloride or of magnesium oxide (heading 9001); (ij) Billiard chalks (heading 9504); or (k) Writing or drawing chalks or tailors' chalks (heading 9609). 3. Any products classifiable in heading 2517 and any other heading of the chapter are to be classified in heading 2517. 4. Heading 2530 applies, inter alia, to: vermiculite, perlite and chlorites, unexpanded; earth colors, whether or not calcined or mixed together; natural micaceous iron oxides; meerschaum (whether or not in polished pieces); amber; agglomerated meerschaum and agglomerated amber, in plates, rods, sticks or similar forms, not worked after molding; jet; strontianite (whether or not calcined), other than strontium oxide; broken pieces of pottery, brick or concrete. Statistical Note 1. For the purposes of heading 2525: (a) The term "split block mica" means mica, not exceeding 0.508 mm in thickness, that has been split and selected within a tolerance of 0.203 mm, but which has not been cut or stamped to dimensions, shape or form; (b) The term "mica splittings" means mica laminae in book-form or book-pack, or in loose pack, suitable for use in the manufacture of agglomerated (built-up) mica included in heading 6815. Harmonized Tariff Schedule of the United States Revision 29 (2025) Annotated for Statistical Reporting Purposes V 25-2

    Section notes

    SECTION V MINERAL PRODUCTS V-1 Harmonized Tariff Schedule of the United States Revision 29 (2025) Annotated for Statistical Reporting Purposes V-2 Harmonized Tariff Schedule of the United States Revision 29 (2025) Annotated for Statistical Reporting Purposes

    Latest update

    Last updated

    November 15, 2025

    Revised every January & July

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