The density of rocks depends on the mineral contents and is therefore a helpful property for the discrimination of lithological units. It is also used for the calculation of several other properties, like the heat production rate from potassium, uranium and thorium contents, volume susceptibility, thermal conductivity, etc. The density of cuttings and cores is determined by the Archimedian method. The weight of the sample is determined in air and in water. Knowing the density of water, the volume and the density of the sample is calculated. Air adsorbed by the large surface of the cuttings causes errors in the calculated volume. Therefore, the specific surface of the cuttings is minimized by using only cuttings greater than 2 mm in diameter. The depth interval of the measurements is generally 2 m.