Density of Gneiss: Porosity, Velocity and Strength Values
The density of gneiss typically runs from 2.6 to 2.9 g/cm3, or about 2600 to 2900 kg/m3, with porosity of 0.5 to 1.5 percent. Compressional seismic velocity sits near 5 to 6 km/s and unconfined compressive strength spans 50 to 200 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 2.9 g/cm3 |
| Porosity | 0.5 to 1.5 percent |
| P wave velocity | 5 to 6 km/s |
| Unconfined compressive strength | 50 to 200 MPa |
| Mass of 1 m3 (mid density) | about 2.75 tonnes |
Why the range
Banded high grade metamorphic rock whose strength depends on which way you load the banding. 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 convert between specific gravity and density without doing the arithmetic twice.
- Two Way Time to Depth Converter, to carry this velocity into a depth conversion.
- Density of Slate, for the neighbouring rock type in the same section.
- Density of Sandstone, for the comparison that decides which unit you are actually looking at.
- USGS Mineral Resources Program, published rock and mineral property data.