The average grain-density of a sample can be calculated from its mineralogy and TOC content, or measured directly by He-pycnometry. Known quantities of helium gas are expanded into a cell containing the sample, at different pressures but constant temperature. A gas law (corrected for non-ideality) is used to calculate the skeletal volume of the sample, from which the grain density is obtained, using the sample mass.
If the exact volume of the sample is known, for instance with plug samples, He-pycnometry can be used to analyse the effective porosity of samples. Qmineral can handle different sample sizes.
Figure. Qmineral uses the AccuPyc 1340 from Micromeritics for He-pycnometry measurements.