compressive strength of different rocks

The compressive strength of rocks varies widely depending on their type, mineral composition, porosity, and geological formation. Below is a general comparison of the uniaxial compressive strength (UCS) of common rock types:

Compressive Strength of Different Rocks (Approximate Range)
| Rock Type | Uniaxial Compressive Strength (MPa) | Typical Uses & Notes |
|————————–|——————————–|————————–|
| Sedimentary Rocks | | |
| Shale | 10 – 200 MPa | Weak, prone to weathering |
| Sandstone | 20 – 170 MPa | Variable strength based on cementation |
| Limestone | 30 – 250 MPa | Used in construction, varies with purity |
| Dolomite | 50 – 250 MPa | Stronger than limestone |
| Chalk | < 10 MPa | Very weak, crumbles easily |
| Coal | 5 – 50 MPa | Low strength, used for fuel |
| Igneous Rocks | | |
| Basalt | 100 – 300 MPa | Very strong, used in construction |
| Granite | 100 – 350 MPa | High strength, durable for buildings |
| Gabbro | 150 – 300 MPa | Dense and strong |
| Pumice | < 10 MPa | Highly porous, very weak |
| Obsidian | ~200 MPa | Glassy but brittle |
| Metamorphic Rocks | | |
| Marble | 50 – 200 MPa | Used in sculpture & flooring |
| Quartzite | 150 – 400 MPa | Extremely hard & durable |
| Slate | 50 – 200 MPa | Splits into thin sheets |
| Gneiss | 100 – 300 MPa | Similar to granite |

Factors Affecting Compressive Strength:
1. Mineral Composition (e.g., quartz-rich rocks are stronger).
2. Porosity & Fractures (higher porosity reduces strength).
3. Grain Size & Texture (fine-grained rocks are usually stronger).
4. Weathering & Alteration (weathered rocksse strength).
5. Anisotropy (strength varies with direction in layered rocks like shale).

Testing