Fe-X-ray Absorption Near Edge Spectroscopy (Fe-XANES) spectra from clinopyroxene powders and crystals with known and unknown Fe3+/FeTotal contents with supporting major element compositions from electron probe microanalysis (EPMA) and crystal orientation data from electron backscattered diffraction (EBSD). These data were collected in support of an article titled: 'Estimating Fe valence in magmatic clinopyroxene crystals: Fe-XANES versus electron microprobe'. Clinopyroxene crystals with known Fe3+/FeTotal contents were sourced from collections at the University of Manchester and Manchester Museum, and have been described previously by Neave et al. (2024a; doi: 10.1007/s00410-023-02080-2). Clinopyroxene crystals with known Fe3+/FeTotal contents are from Skuggafjöll (Iceland) and Pico Island (Azores) and have been described previously by Neave et al. (2024b; doi: 10.1007/s00410-024-02144-x). These data were acquired as part of David A. Neave's NERC IRF (NE/T011106/1) between January 2020 and February 2023. Fe-XANES was performed at Diamond Light Source Beamline I18 (SP31428) in February 2023. EPMA was performed at the University of Bristol in Spring 2022. Electron Backscattered Diffraction (EBSD) was performed the University of Liverpool in May 2023. These data were collected to evaluate whether Fe-XANES, which has seen increasingly widespread use for determining Fe valence in isotropic glasses and minerals in recent years, could be routinely used to determine Fe valence in large numbers of anisotropic clinopyroxene crystals. Our motivation stems from ultimately seeking to develop new tools for estimating oxygen fugacity from magmatic clinopyroxene crystals. This work was initially designed to capitalise on two articles on clinopyroxene Fe-XANES that have since been retracted without further comment; we thus present an evaluation that transparently highlights the myriad challenges associated with clinopyroxene Fe-XANES. This repository contains EPMA, Fe-XANES and EBSD data supporting the manuscript; Neave, D. A., Mariani, E., Stewart, A. G., Hartley, M. E., Shorttle, O., & Humphreys, M. C. S. (2026). Estimating Fe valence in magmatic clinopyroxene crystals: Fe-XANES versus electron microprobe. Advances in Geochemistry and Cosmochemistry, 2(1), 1061. https://doi.org/10.33063/agc.v2i1.1061
