Three-dimensional X-ray microtomography dataset of Laacher See and Vesuvius pumice before and after experimental tumbling

This dataset contains three-dimensional X-ray micro-computed tomography (micro-CT) data of pumice clasts from Laacher See volcano (Germany) and Vesuvius volcano (Italy). The data were acquired to investigate the relationship between internal pyroclast textures and their mechanical response during experimental granular transport, with particular emphasis on vesicle and crystal populations. The dataset includes starting material (SM) and clasts subjected to tumbling experiments (T2), in which the generated ash was removed after each experimental time increment. Micro-CT analyses were performed at different spatial resolutions (Whole, Zoom, and Very High Resolution – VHR) using a ZEISS Xradia 410 Versa microscope at the Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Vesuviano (INGV-OV), Naples, Italy, in December 2025. The data are provided as reconstructed three-dimensional greyscale volumes in the proprietary ZEISS Xradia TXM (.txm) format. These volumes can be used for further image processing, segmentation, and quantitative characterization of vesicles, crystals, porosity, and internal textural heterogeneity. The repository also includes a README file describing the dataset and its naming conventions, and a dataset inventory providing sample identifiers, volcanic origin, experimental conditions, and scan information. Funding: Data acquisition was supported by the EXCITE2 Transnational Access programme (Project ID: E2-C3-97), funded by the European Union's Horizon Europe research and innovation programme under grant agreement No. 101131765, at INGV-OV, Naples, Italy.