This dataset contains scanning electron microscope (SEM) backscatter images of magma plug rock samples collected from ballistically ejected volcanic blocks at Soufrière Hills Volcano (Montserrat, West Indies) and Reventador and Sangay volcanoes (Ecuador, South America). The dataset comprises high-resolution SEM backscatter images of polished rock blocks acquired at three magnifications (×50, ×300 and ×1000) to show the macro and micro-textures, crystal textures at all scales and mineral distributions. A metadata files is included which has sample information; including information on rock type, eruption and textures; along with information on SEM settings. An accompanying metadata file provides sample details, rock type, eruption data and textures, and SEM settings. The data were collected, between August 2024 and January 2026, as part of the NERC-funded project NE/W008033/1 The explosivity of volcanic eruptions: Quantifying the critical role of permeability in magmas.