① Its coefficient of linear expansion is extremely low (about 1/10~1/20 of ordinary glass)

② Resistant to high temperatures of 1100 ℃~1200 ℃ and can withstand 1400 ℃ in the short term;

③ , with a hardness of Mohs 7

④ Has strong tolerance to general acids except hydrofluoric acid and hot phosphoric acid;

⑤ At the same time, it has good electrical insulation and can transmit ultraviolet and infrared spectra. ‌