|
|
|
|
|
|
GEMMOLOGICAL PROPERTIES
Iolite
Family: |
Cordierite |
Crystal System: |
Orthorhombic |
Specific Gravity: |
2.57 - 2.66 |
Hardness: |
7 - 7.5 |
Refractive Index: |
1.52 - 1.57 |
Chemical Composition: |
(Mg,Fe)2Al4Si5O18 |
Birefringence: |
0.008 - 0.012 |
Pleochroism: |
Strong, Dichroic. Yellow-Brown & Blue |
Lustre: |
Vitreous |
Fracture: |
Chonchoidal |
Cleavage: |
Poor (010) |
|
|
|
|
|
|