Coal
| Property | Specification |
| Appearance | Black or brownish-black solid |
| Shape | Irregular lumps, fine particles, or dust |
| Density | 1.1 - 1.5 g/cm³ |
| Hardness | Varies; generally 2 - 5 on the Mohs scale |
| Moisture Content | 1% - 40% |
| Volatile Matter | 10% - 50% |
| Ash Content | 5% - 40% |
| Fixed Carbon | 30% - 80% |
| Calorific Value | 18 - 30 MJ/kg (depending on grade) |
| Sulfur Content | 0.5% - 6% |
| Carbon Content | 60% - 90% |
| Fusibility (Softening Point) | 1,000°C - 1,200°C |
| Conductivity | Low electrical conductivity |
| Odor | Odorless (can have a sulfurous smell when burning) |