Industrial Minerals
Quality and testing
A mineral is only as good as the certificate that comes with it — and only as good as the lot it was measured on.
What travels with every shipment
- Mill test certificate for the lot, with the measured values, not the range
- Certificate of analysis signed by the processing plant
- Safety data sheet in the US 16-section GHS format
- Certificate of origin and the commercial invoice and packing list
- Asbestos test report where the mineral and the application call for one
If a document you need is not on that list — a food-contact statement, a REACH-style declaration, a heavy-metals assay — ask before you order rather than after. Most are obtainable; some take a week.
Typical range versus specification
Every mineral page on this site publishes typical ranges. That is what the mineral does as a class, and it is what you need to decide whether to ask for a sample.
It is not a specification. The numbers that govern your order are the ones measured on your lot and printed on its mill test certificate. When we agree a supply arrangement, the certified limits go in the contract and become guaranteed — at which point they stop being typical and start being ours to meet.
Any supplier who gives you one number with no range and no method is telling you less than they know.
Testing before shipment
| Test | Method | When |
|---|---|---|
| Chemistry | XRF or wet analysis for the oxides that matter to your application | Every lot |
| Particle size | Laser diffraction for D50 and top cut; wet sieve residue | Every lot |
| Brightness and whiteness | Elrepho on dry powder, ISO basis | Where brightness is specified |
| Oil absorption | Spatula rub-out | Filler and extender grades |
| Moisture and loss on ignition | Oven and furnace | Every lot |
| Specific gravity | Pycnometer — the defining test for barytes | Where density is specified |
| Asbestos | Polarised light microscopy and transmission electron microscopy | Talc for US destinations |
| API conformance | API 13A for drilling-grade barytes and bentonite | Drilling grades |
Third-party verification at an independent US laboratory is available on request and is normal for a first shipment on a new contract. We will arrange it and share the result whether it is convenient or not.
Talc and asbestos, plainly
Talc and asbestiform amphiboles can occur in related geology, which is why this is the first question a serious buyer asks. Our position is straightforward: ore is taken from deposits worked for industrial talc, lots bound for the United States are tested by both polarised light microscopy and transmission electron microscopy, and the report travels with the shipment.
There is currently no US federal rule requiring asbestos testing of cosmetic talc — a standardised-method rule was proposed in December 2024 and withdrawn in November 2025 — but the absence of a rule is not the point. Buyers demand the testing, the litigation history is substantial, and we would not supply without it.
If your application is cosmetic or pharmaceutical, say so on the enquiry. That is a different supply chain with different documentation, not a different grade.
Handling and worker safety
Mineral dusts are regulated as occupational hazards in the United States. Respirable crystalline silica — present in silica sand, quartz powder and, in small quantities, in several other minerals — carries a permissible exposure limit and, in many operations, a requirement for a written exposure control plan. Talc and other nuisance dusts carry their own limits.
A US-format safety data sheet ships with every consignment and is sent ahead of the material on request. Handling controls in your plant are yours to set; the information you need to set them is ours to provide.
Want to see a certificate before you order?
Ask for a sample and we will send the mill test certificate for that exact lot with it.