| Name |
|
Cordierite
(Dichroite) |
| Chemistry |
|
Mg2Al3[AlSi5O18] |
| Hardness |
|
7 |
| Lustre |
|
greasy - vitreous |
| Colour |
|
colourless, grey, violet, blue, brown |
| Streak |
|
white |
| Density [g/cm3] |
|
2.6 |
| Crystal habit |
|
orthorhombic, crystals
rarely, short columnar |
| Cleavage, Fracture |
|
fracture conchoidal |
| other characteristics
and occurrences |
|
iolite = blue violet
(gemstone variety)
metamorphic mineral, primarily in gneiss |
 |
|
|