- Quarzwerke GmbH | Germany
- Quarzwerke Österreich GmbH | Austria
- Amberger Kaolinwerke Eduard Kick GmbH & Co. KG | Germany
- Caminauer Kaolinwerk GmbH | Germany
- KiZPPS Osiecznica Sp.z.o.o. | Poland
- Provodinské pisky a.s. | Czech Republic
- Minorit s.r.o. | Czech Republic
- Kerkosand spol.s.r.o. | Slovakia
- Surmin-Kaolin S.A. | Poland
- ZAO Balaschejskie Peski | Russian Federation
- TKSM Biała Góra Sp. z o.o. | Poland