Illite is a kind of mica clay minerals with rich potassium silicate, It is also named as water white mica. Formula as K0.75 Al1.75 (R) Si3.5 Al0.5 O10 (OH) 2, R=metal ions, mainly for the bivalent magnesium, ferrous iron. It is showed as irregular scaly under the electron microscope . Hardness 1-2, no swelling and no plasticity.
Chemical composition
| SiO2 | Al2O3 | Fe2O3 | TiO2 | CaO | MgO | k2O | Na2O |
| 46.27 | 34.81 | 0.28 | 0.66 | 0.42 | 0.18 | 8.94 | 0.99 |
Physicial
| Whiteness | Moisture(%) | PH | Bulk density (g/cm3) | Size |
| 78-80 | 0.5max | 7-7.5 | 2.6-2.9 | 800-2000 mesh |
