A Outer clean and transparent, without visible bubble and impurity. B Specific density: 2.5g/cm3 C Index of refraction: Nd=1.55 D Content of Sio2: =80% E Spherical beads: =85% F Coated beads to avoid moisture and falling down. G Hardness: 6-7 H coating : silicon oil 25kg/bag or 1000kg/bag
