| Item |
Properties |
| Absolute specific gravity |
2.7-3.0 g/cm3 |
| Hardness |
2.8-3.2 Mohs |
| Modulus of elasticity |
1.6-2.1×106 kg/cm2 |
| Coefficient of expansion |
Perpendicular to cleavage plane: 15-25×10‐6 /K
Parallel to cleavage planes :8-9×10‐6 /K |
| Specific heat |
880 J/(kg・K) |
| Thermal conductivity |
0.55-0.79 J/(s・m・K) |
| Melting point |
1250 ℃ |
| Calcining temperature |
550 ℃ (Dehydrating temperature of OH in crystal) |
| Volume resitivity |
1014-1015 ohm・cm |
| Relative permittivity |
7 (at 50〜108 Hz) |
| Power factor (Loss tangent) |
2-10×10-4 tanδ(at 50〜108
Hz) |
| Dielectric strength |
25 kV/mm |
| Color |
Browninsh transparent (Super-fine powder appears white) |
| Refractive-index |
n1=1.5993
n2=1.5944
n3=1.5612 |
