The density and porosity of meteorites from the Vatican collection

We have developed a nondestructive technique to measure the densities and porosities of large (50 g to several kilogram) meteorite samples and have begun a systematic measurement program starting with meteorites from the Vatican Observatory collection. Our technique utilizes a modified Archimedean method (40 mu m glass spheres substituting for the fluid) to determine bulk density, and an unusually large He pycnometer to determine grain density. From these, the porosity is calculated. We report here our first results for 89 samples (nearly doubling the published database on porosities of meteorite hand samples), including porosities of 35 different meteorites. These include several types not previously reported: eight iron meteorites, six stony-iron meteorites, an enstatite chondrite, the CI carbonaceous chondrite Orgueil, and the shergottite-nakhlatite-chassignite (SNC) meteorite Nakhla.