Density of Granite: Porosity, Velocity and Strength Values
The density of granite typically runs from 2.6 to 2.7 g/cm3, or about 2600 to 2700 kg/m3, with porosity of 0.5 to 1.5 percent. Compressional seismic velocity sits near 5.5 to 6 km/s and unconfined compressive strength spans 100 to 250 MPa. The table below collects the values; the notes explain why the ranges are as wide as they are.
| Property | Typical range |
|---|---|
| Density | 2.6 to 2.7 g/cm3 |
| Porosity | 0.5 to 1.5 percent |
| P wave velocity | 5.5 to 6 km/s |
| Unconfined compressive strength | 100 to 250 MPa |
| Mass of 1 m3 (mid density) | about 2.65 tonnes |
Why the range
The reference rock of the continental crust: quartz and feldspar dominated, dense, tight, and strong. Weathered granite loses strength fast, so quarry fresh values and outcrop values live in different worlds. For design work, treat these as screening values: a specific site deserves specific testing, and the calculators linked below show how each number is measured and used.
Use these values
- Rock Density Calculator to build density from mineral composition.
- Porosity Calculator to measure porosity from well logs.
- The Property Library for every rock, soil, and mineral on this site.
Related Calculators and Reference
- Rock Density and Specific Gravity Calculator, to turn a specific gravity straight into a density in whichever unit the report wants.
- Two Way Time to Depth Converter, because the velocity quoted here is what a time to depth conversion runs on.
- Density of Coal, for the lithology most often logged next to it.
- Density of Tuff, for the neighbouring rock type in the same section.
- USGS Mineral Resources Program, published rock and mineral property data.