| Silicon Oxide | Aluminum Oxide | Magnesium Oxide |
| Titanium Oxide | Zirconium Oxide |
| AGY Holding Corp. | GBC Materials | H.C. Starck |
| Magyar Aluminium | Malvern Minerals Company | MarkeTech |
| Microtherm Group | Piezo Kinetics, Inc. | St. Cloud Mining Company |
| Thermal Ceramics | Wieland | Zircar Ceramics |