gems, tourmaline, Ethiopia, paraíba tourmaline, cuprian tourmaline

Reports the June 2026 discovery of Cu-bearing tourmaline from Abulo Rukessa (Abuloo), Guji Zone, southern Ethiopia, and presents gemmological, spectroscopic and chemical characterization of 14 reportedly representative stones. Standard testing, microscopy, polarized UV-Vis-NIR and Raman spectroscopy, together with LA-ICP-TOF-MS, showed all samples to belong to the elbaite–fluor-elbaite series. Copper generally exceeded iron, with Cu ranging from 373 to 26,157 ppmw and Fe from 2 to 7,368 ppmw. Bismuth contents formed three distinct high-, intermediate- and low-Bi groups, and these tiers occurred as growth zoning within individual stones. Comparison with 1,653 analyses of Cu-bearing tourmalines from Brazil, Mozambique and Nigeria showed vanadium to be the clearest provenance discriminator, with Ethiopian samples containing 42.9–146 ppmw V, compared with a maximum of 20.3 ppmw in the comparison set. t-SNE statistical analysis likewise separated the Ethiopian data into a distinct compositional field. Rare-earth-element patterns were enriched in light REE and showed mild Eu anomalies. Representative ordinary-ray Vis-NIR spectra displayed stronger Cu²⁺ absorption near 900 nm than the combined Cu²⁺ + Fe²⁺ absorption near 700 nm, and the analyzed faceted stones therefore meet LMHC criteria for the trade designation “paraíba tourmaline.”