IMA-CNMNC guidelines for assessing the natural geological origin of minerals

Abstract. Establishing whether a newly discovered solid phase qualifies as a mineral of natural geological origin requires a thorough evaluation of its context of occurrence. This paper builds on the existing guidelines of the Commission on New Minerals, Nomenclature and Classification (CNMNC) and introduces updated recommendations, developed with input from the International Mineralogical Association (IMA) Mediation Committee (MC), aimed at strengthening the credibility of CNMNC mineral proposals, particularly for species with uncertain origins. Through a critical re-evaluation of three case studies (tewite, wumuite, and liguowuite), it is shown how textural and contextual evidence, or the lack thereof, impacts the assessment of natural authenticity. We propose an enhanced documentation checklist that incorporates geological, textural, and isotopic criteria to reduce ambiguity, avoid misinterpretation of anthropogenic phases, and safeguard against potential fraud.