| Silicon Oxide | Aluminum Oxide | Magnesium Oxide |
| Titanium Oxide | Zirconium Oxide |
| AGY Holding Corp. | Anderman Ceramics | China-Yixing Longly Refractories Co. Ltd |
| Gouda Vuurvast | Michelman® | Minelco Inc. |
| Nabaltec GmbH | NanoScale | Potters Industries |
| Sapco | Skamol Group | Zircar Ceramics |