Table 2. Chemical composition of the natural mineral materials of Song-Gang® bio-stone (% DM, dry matter basis)
| Minerals | Song-Gang® bio-stone |
| SiO2 | 73.4 |
| Al2O3 | 15.5 |
| Fe2O3 | 0.87 |
| CaO | 0.91 |
| MgO | 0.09 |
| K2O | 4.31 |
| Na2O | 4.19 |
| TiO2 | 0.03 |
Values are means of duplicate samples.