Corning HPFS 7989,7980,8655 Fused Silica, known throughout the industry for their consistent, repeatable performance. Corning offer many different grade of fused silica to support various product applications. these are high purity non-crystalline silica glasses with excellent optical quality. PHYO OPTICS sourcing from Corning cooperation for the exact material to meet the customer drawings request along with the material certificates.