This dataset contains major and trace element compositions for a sample of basalt recovered from Rangitoto Island, New Zealand. Both bulk rock and microanalytical observations are made and presented. Electron probe microanalysis (EPMA) results detail the compositions of individual phases within the basalt including olivine, clinopyroxene, plagioclase feldspar, glass, and polyphase microcrystalline groundmass. Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) results detail trace element compositions for the glass as well as on select olivine grains. X-Ray fluorescence (XRF) data detailing major and minor element oxide concentrations were gathered using bulk rock powders. Additional tables detail the statistical analysis of the microanalytical data. Outliers within the glass and groundmass data populations were identified, and the summary statistics of this quality control processing are presented in a separate table. The trimmed glass and groundmass data are presented separately. In this data table, the compositions are provided after transformation into isometric- and centered log-ratio coordinates (for an explanation of these coordinates, please see the associated publication).