Quartz Tube 1" & 1.57" ( 25 - 40 mm ) 2" & 2.36" (50 - 60mm) 3" & 3.14" ( 75 - 80mm) 4", 4.37" 4.5" & 5" 6", 8" 8.5" & 11" Fused Quartz Glass Typical Physical Properties PROPERTY ENGLISH & METRIC SYSTEM VALUE INTERNATIONAL SYSTEM OF UNITS (SI) VALUE Density 2.2 gm/cm3 2.2 x 103kg/m3 Hardness 5.5 - 6.5 Mohs' Scale 570KHN100 Design Tensile Strength 7,000 psi 4.8 x 107Pa (N/..