The opaque quality comes from quartz sands of high purity when reduced to a molten state at a temperature of approximately 2000° C. The high temperature produces a vitreous material characterized by the presence of a multitude of gaseous micro-bubbles. These bubbles diffract light, giving the material its opacity. The term opaque silica is mainly used for molded or centrifuged parts, while the product obtained by drawing is normally referred to as translucent. 
 
Opaque silica glass offers a number of exceptional properties, such as: 

Extreme Hardness 

Low Expansion 

Excellent High Temperature Resistance 

Extreme Chemical Purity 

Excellent Corrosion Resistance 

Excellent Electrical Insulation Properties 

Remarkable Stability Under Atomic Bombardment