1) complete conversion of the quartz, the true specific gravity is low (2.34 or less), a low content of residual silica (1%) when using a small volume change. 
2) low porosity, bulk density, high strength, good wear resistance. 
3) high purity, load softening point temperature> 1650 ℃, high temperature deformation. 
4) good resistance to high temperature creep properties 
5) low thermal expansion, high temperature volume stability. 
6) quality indicators of stability, appearance neat, precise size.