The processing and properties of Types I and II fused quartz optics and Types III and IV synthetic fused silica optics are compared with new organometallic sol-gel derived (Types V and VI) gel-silica optics. Type V gel-silica has excellent transmission from 165 nm to 4200 nm with no OH absorption peaks. Other physical properties and structural characteristics of Type V gel-silica are similar to high grade fused silica but offer the advantages of near net shape cast4ng, including internal cavities, and a lower coefficient of thermal expansion of 0.2 x 10-6 cm/cm compared with 0.55 x 10-6 cm/cm. Optically transparent porous gel silica (Type VI) has a UV cut-off ranging from 250-300 nm. Type VI gel-silica optics has a density as low as 60% of Types I-V silica and can be impregnated with up to 30 to 40% by volume of a second phase optically active organic or inorganic compound.