Analysis
HTS 2507.00.00 covers kaolin and other kaolinic clays, whether or not calcined under heading 2507 (kaolin and other kaolinic clays, whether or not calcined).
Goods classified here enter the United States duty-free at the general (normal trade relations) rate, as do about 91% of the 78 tariff lines in chapter 25. Free here means free of the base duty only: origin-specific Chapter 99 duties such as Section 301 can still be owed.
It is the only US line under subheading 2507.00, so the six-digit code used by every Harmonized System country and the eight-digit US line describe the same goods; a foreign tariff or an exporter's invoice showing 2507.00 points straight here.
Census statistics map these goods to NAICS 21232 (Sand, Gravel, Clay, and Ceramic and Refractory Minerals Mining and Quarrying), an industry of 2,617 US establishments employing 36,740 people. That is the industry code a US manufacturer of the same product would normally use.
Every edition we compared, from Jan 2023 to Oct 2026 (Rev. 22), shows the same general rate of Free.