Product classification
HS code for Industrial clays: 2508.40
Clays (excluding expanded clays of heading no. 6806), n.e.c. in heading no. 2508, whether or not calcined.
Classification of industrial clays under HS 2508.40
Industrial clays are classified under HS code 2508.40. This code is part of Chapter 25, which includes salt, sulfur, earths, stone, plastering materials, lime, and cement. Heading 2508 covers various natural clays, whether or not calcined, but excludes expanded clays. Subheading 2508.40 is the "Other clays" category, encompassing industrial clays that are not kaolin (2507), bentonite (2508.10), fire-clay (2508.30), or andalusite/kyanite (2508.50). These clays are used in a wide range of industrial applications, including the manufacture of ceramics, refractories, paper, and rubber. They are valued for their plasticity, heat resistance, and chemical stability. The classification applies to the clay in its natural state or after it has been washed, ground, or calcined (heated to remove volatile impurities). However, if the clay has been further processed into a finished product or mixed with other materials to form a composite, it may move to Chapter 68 or 69. For customs purposes, it is important to demonstrate that the clay has not been mixed with other minerals in a way that changes its fundamental character as a natural earth. Calcination is permitted under this heading, which is a common process for industrial clays to improve their physical properties for specific manufacturing uses.
- Covers
- Common industrial clay
- Ball clay for ceramics
- Fuller's earth (non-activated)
- Calcined industrial clay
- Plastic clay for refractory use
- Shale clay for brick manufacturing
- Also under 2508.40
- Oil-Dri Corporation (absorbent clays)
- EP Minerals (diatomaceous earth)
- Tolsa (sepiolite/palygorskite)
- Active Minerals International (attapulgite)
- Clariant (specialty clays).
Codes often confused with 2508.40
Common mistake. Industrial clays are often confused with Kaolin (2507.00) or Bentonite (2508.10). Another common error is classifying expanded clays (used for insulation) under 2508.40, whereas they belong in 6806. Clays that have been activated with chemicals for bleaching or filtering purposes are classified under 3802.90.
Top exporters and importers of HS 250840 (the code used for industrial clays), 2025
In 2025, the largest exporter of HS 250840 (the code used for industrial clays) in UN Comtrade data was the United States, with 22% of world exports; the largest importer in UN Comtrade data was Italy, with 21% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 250840, not only industrial clays.
Top exporters 2025 · share of world exports
- 1 United States $152M 22% of world exports
- 2 Spain $119M 17% of world exports
- 3 Germany $101M 14% of world exports
World total: $705M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Italy $179M 21% of world imports
- 2 Netherlands $58M 6.9% of world imports
- 3 Canada $49M 5.8% of world imports
World total: $843M Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM codes for industrial clays
Brazil splits HS 2508.40 into 2 NCM codes. Pick the one that matches your product:
- 2508.40.10Plastic clays, under 1.5% Fe2O3, over 12% LOI
- 2508.40.90Other clays, not bentonite or fireclay
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about industrial clays
What is the HS code for Industrial clays?
The HS code for Industrial clays is 250840 (Clays (excluding expanded clays of heading no. 6806); n.e.c. in heading no. 2508, whether or not calcined). The HS code for industrial clays not elsewhere specified (excluding expanded clays) is 2508.40.
How do I classify Industrial clays for customs?
Industrial clays is classified under HS code 250840 — Clays (excluding expanded clays of heading no. 6806); n.e.c. in heading no. 2508, whether or not calcined. This is a 6-digit subheading level code.
Is calcined clay classified differently?
No, heading 2508 specifically includes clays whether or not they have been calcined, provided they haven't been mixed with other materials.
Which countries are the top exporters of industrial clays (HS 250840)?
In 2025, the top exporters of HS 250840 (the code used for industrial clays) in UN Comtrade data were the United States ($152M, 22% of world exports), Spain ($119M) and Germany ($101M). World exports came to about $705M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of industrial clays (HS 250840)?
In 2025, the top importers of HS 250840 (the code used for industrial clays) in UN Comtrade data were Italy ($179M, 21% of world imports), the Netherlands ($58M) and Canada ($49M). World imports came to about $843M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Industrial clays the same in all countries?
The base HS code 250840 for Industrial clays is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for industrial clays in Brazil?
Brazil splits HS 250840 into 2 NCM codes, so the right one for industrial clays depends on the product's details: 2508.40.10 (Plastic clays, under 1.5% Fe2O3, over 12% LOI), 2508.40.90 (Other clays, not bentonite or fireclay).