Fayalit is a mineral Fe 2 SiO 4 , an iron - rich extreme member of the olivine group (fayalit - forsterite ). The name comes from the name of Fayal Island ( Azores ), where it was first discovered (H. G. Gmelin, 1840).
| Fayalit | |
|---|---|
 | |
| Formula | Fe 2 SiO 4 |
| Impurity | Mn |
| Physical properties | |
| Colour | Brown, yellow, black |
| Trait color | White |
| Shine | Glass |
| Transparency | Transparent - Translucent |
| Hardness | 6.5 |
| Density | 4.39 g / cm³ |
| Syngonia | Rhombic (planaxial) |
Fayalit, like olivine, is common among acidic and alkaline igneous rocks , and is also often found in iron-rich metamorphic rocks .
Despite the relatively high hardness , it is not used as an ornamental stone.
It is soluble in hydrochloric acid with the precipitation of a jelly-like silica .
Compressive strength σ compress - 196.1 ÷ 254.8 MPa; [one]
Microhardness 7.48 GPa; [one]
The linear coefficient of thermal expansion is 102 × 10 -7 1 / ° С (in the temperature range of 20 ÷ 800 ° С). [one]
Notes
- ↑ 1 2 3 Vegman E.F., Pyrikov A.N., Jacques A.R. Intensification of the agglomeration process. - M.: Mechanical Engineering, 1995. - S. 106. - 126 p.: Ill. with. - ISBN 5-217-02764-9 .