Product classification
HS code for Stone millstones: 6804.23
Millstones, grindstones, grinding wheels and the like, of natural stone.
Classification of stone millstones under HS 6804.23
HS code 6804.23 is reserved for millstones, grindstones, and grinding wheels made specifically of natural stone. These items are used for grinding, sharpening, polishing, or cutting various materials. The classification is determined by the material composition—natural stone—as opposed to agglomerated abrasives or ceramics. These tools are essential in various industrial and artisanal processes, from grain milling to tool sharpening. The Harmonized System distinguishes between natural stone tools and those made from synthetic or bonded abrasive materials. The classification under 6804.23 applies regardless of whether the stone is mounted on a spindle or frame, provided the stone itself is the functional component. This ensures that traditional natural stone implements are correctly identified for trade and regulatory purposes. The durability and specific abrasive qualities of natural stones like sandstone or granite are the reasons they are still utilized in specific sectors. This code excludes tools where the stone is merely a decorative element or where the grinding is performed by a different material coated onto a stone base.
- Covers
- Natural stone millstones for grain
- Natural stone grindstones for sharpening
- Pulping stones of natural stone
- Polishing stones for metalwork
- Natural stone wheels for cutting
- Also under 6804.23
- Norton natural sharpening stones
- Naniwa natural waterstones
- various artisanal Arkansas stones
- traditional scythe sharpening stones
Codes often confused with 6804.23
Common mistake. The most frequent misclassification is with HS code 6804.22, which covers millstones and grindstones made of agglomerated abrasives or ceramics. It is vital to verify if the item is a single piece of natural stone or a composite material. Additionally, complete machinery for milling grain is classified under HS code 8437; 6804.23 only covers the stone component itself, even if it is imported as a replacement part for such a machine.
Top exporters and importers of HS 680423 (the code used for stone millstones), 2025
In 2025, the largest exporter of HS 680423 (the code used for stone millstones) in UN Comtrade data was China, with 27% of world exports; the largest importer in UN Comtrade data was the United States, 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 680423, not only stone millstones.
Top exporters 2025 · share of world exports
- 1 China $17M 27% of world exports
- 2 Mexico $12M 20% of world exports
- 3 United States $7.7M 12% of world exports
World total: $63M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $19M 21% of world imports
- 2 Mexico $8.1M 8.9% of world imports
- 3 India $7.1M 7.8% of world imports
World total: $91M 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 code for stone millstones
Brazil classifies stone millstones under NCM 6804.23.00: HS 6804.23 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about stone millstones
What is the HS code for Stone millstones?
The HS code for Stone millstones is 680423 (Millstones, grindstones, grinding wheels and the like; of natural stone). The HS code for millstones and grindstones made of natural stone is 6804.23.
How do I classify Stone millstones for customs?
Stone millstones is classified under HS code 680423 — Millstones, grindstones, grinding wheels and the like; of natural stone. This is a 6-digit subheading level code.
Does this include synthetic grinding wheels?
No, synthetic or agglomerated grinding wheels are classified under HS code 6804.22, not 6804.23.
Which countries are the top exporters of stone millstones (HS 680423)?
In 2025, the top exporters of HS 680423 (the code used for stone millstones) in UN Comtrade data were China ($17M, 27% of world exports), Mexico ($12M) and the United States ($7.7M). World exports came to about $63M, 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 stone millstones (HS 680423)?
In 2025, the top importers of HS 680423 (the code used for stone millstones) in UN Comtrade data were the United States ($19M, 21% of world imports), Mexico ($8.1M) and India ($7.1M). World imports came to about $91M, 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 Stone millstones the same in all countries?
The base HS code 680423 for Stone millstones 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 stone millstones in Brazil?
In Brazil, stone millstones (HS 680423) is classified under NCM 6804.23.00.