This dataset contains the raw X-Ray diffraction (XRD) analysis and stable isotope data, raw and processed, for samples from two different field locations, sample HR5 (Slag) from Harrington, Cumbria, UK (54.608278N, -3.570164W) and sample 22CCT1N6 (Ultramafic mine tailings) from Clinton Creek Mine, Yukon, Canada (64.457222N, -140.710833W). The data was collected in between 2023-2025. The XRD data was collected for the purpose of identifying mineralogy of the collected samples. The stable isotope data was collected for the purpose of identifying whether the carbonate minerals in the collected samples contained atmospheric carbon dioxide. The data was collected by John MacDonald, Charlotte Slaymark and Robin Hilderman (University of Glasgow) who retain the original data. Data underpins manuscript "The Widespread Potential for Rapid Formation of Anthropogenic Sedimentary Rocks" in press