1. Agc Inc (Formerly Asahi Glass Co Ltd)
2. Beijing Kaide Quartz Co Ltd
3. Compagnie De Saint-Gobain S.A.
4. Dow
5. Elkem Asa
6. Ferroglobe Plc
7. Heraeus Holding Gmbh
8. Jiangsu Pacific Quartz Co Ltd
9. Momentive Performance Materials
10. Nihon Dempa Kogyo Co Ltd
11. Nordic Mining Asa
12. Rusnano Group
13. Sibelco
14. Sumco Corporation
15. The Quartz Corporation