Density of Chalk: Porosity, Velocity and Strength Values
The density of chalk typically runs from 1.4 to 2.4 g/cm3, or about 1400 to 2400 kg/m3, with porosity of 15 to 45 percent. Compressional seismic velocity sits near 1.5 to 3 km/s and unconfined compressive strength spans 5 to 30 MPa. The table below collects the values; the notes explain why the ranges are as wide as they are.
| Property | Typical range |
|---|---|
| Density | 1.4 to 2.4 g/cm3 |
| Porosity | 15 to 45 percent |
| P wave velocity | 1.5 to 3 km/s |
| Unconfined compressive strength | 5 to 30 MPa |
| Mass of 1 m3 (mid density) | about 1.90 tonnes |
Why the range
A soft, high porosity limestone that crushes rather than cracks, with foundation behavior all its own. 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 Conglomerate, for the lithology most often logged next to it.
- Density of Schist, for the neighbouring rock type in the same section.
- USGS Mineral Resources Program, published rock and mineral property data.