| Density/(g•cm-3) | 2.35 | | 2.20 |
| Coefficient of the thermal expansion/K-1 | 3.14×10-6 | Average of many samples on cooling between 1000℃ and 100℃; hot-pressed | 0.5 |
| Vickers hardness/(kg•mm-2) | 855
704 | 200 g load
1000 g load | 600-700 |
| Critical stress intensity factor /(MPa•m1/2) | 1.8 | 1000 g load | 1 |
| Fracture strength/MPa | 153±20 | 3-point bending of 0.74 mm diameter fibers | |
| 385±227 | 3-point bending of bars | |
| Young's elastic modulus/GPa | 97.9 | | 70 |
| Index of refraction | 1.58 | At 0.5893 μm | 1.46 |
| Glass transition/℃ | 1350 | Viscosity of 1013 P | 1190 |
| Dielectric constant | 4.4 | 25℃, 10 to 107 Hz pyrolyzed to 1100℃ | 4 |
| Dielectric loss tangent | 0.1 | 25℃, 10 to 107 Hz pyrolyzed to 1100℃ | 10-4 |
| Electrical conductivity /(Ω·cm) -1 | 4×10-13 | 25℃, pyrolyzed to 1100℃ | ~10-22 |