Perlite is a sort of nature glass volcanic ore with 2%-5% combined water inside, Which is formed when acid volcanic lava flow into lakes or oceans and cool rapidly. When perlite ore is expanded, the internal microporous structure makes it has low density, good air permeability and water resistance, so perlite is widely used in horticulture and agriculture etc.
| Physical properties: | |
| Color | white, grey white |
| Shape | granular |
| Microporous structure | open cell |
| Maximum operating temperature | 800 ℃ |
| Max.water absorbtion rate | up to 900% by weight |
| Chemical properties: | |
| Loss on Ignition (1000ºC) | <1.0 |
| SiO2 | 70 ~75% |
| Al2O3 | 12 ~16% |
| Fe2O3 | 0.15～1.5% |
| MgO | 0.2～0.5% |
| CaO | 0.1～2.0% |
| Na2O | 2.5～5.0% |
| K2O | 1.0～4.0% |
