IMA Releases Updated Mineral Nomenclature Guidelines

The International Mineralogical Association (IMA) Commission on New Minerals, Nomenclature and Classification (CNMNC) has published its latest bulletin, Newsletter 93, which sets out updated guidelines for proposing and approving new mineral species. The document was authored by Ferdinando Bosi, Frédéric Hatert, Marco Pasero, and Stuart J. Mills and appeared in volume 38 of the European Journal of Mineralogy in 2026 ¹.

Newsletter 93 revisits several long‑standing conventions that have guided mineralists for decades. Among the key updates is a clearer definition of “nominally anhydrous” versus truly anhydrous minerals, intended to reduce ambiguity when classifying species with trace water contents. The commission also introduced additional criteria regarding crystal structure verification, requiring at least two independent diffraction studies before a candidate can be considered for official recognition.

In addition to rule changes, the newsletter provides examples drawn from recent proposals submitted during the past year. While it does not list each new mineral name explicitly—those details are available in the full IMA database—the bulletin highlights how the committee applied the revised standards to evaluate candidates. These case studies illustrate the practical application of the updated nomenclatural framework and serve as reference points for future submissions.

The authors emphasize that the intent behind the revisions is not to suppress innovation but to ensure consistency across the global community of petrologists and crystallographers. By tightening classification protocols, CNMNC aims to improve reproducibility of mineral identification and facilitate cross‑disciplinary communication between geologists, materials scientists, and gemmological experts.

Bosi noted that the current edition reflects extensive feedback received over the last 12 months, particularly concerning the handling of polymorphic forms and the integration of spectroscopic data into naming decisions. Hatert added that the updated guidelines will be incorporated into the forthcoming IMA “Mineral Names” handbook expected later this year.

Pasero highlighted the importance of maintaining an up‑to‑date registry of approved names; he cited a projected increase of roughly 15 % in newly accepted species over the next two years based on recent submission trends. Mills concluded by underscoring the role of transparency: all rule changes are now openly available online, allowing researchers worldwide to verify compliance before formal proposal.

While Newsletter 93 does not introduce new gemstone varieties per se, its implications ripple through the entire field of mineralogy. Gemmologists who rely on precise chemical and structural descriptors can anticipate more reliable nomenclature when cataloguing rare or previously unclassified stones. Likewise, rockhounding enthusiasts—who often encounter ambiguous labels for local specimens—stand to benefit from clearer terminology that reduces misidentification risks.

In summary, the CNMNC’s latest bulletin represents a significant step toward harmonizing mineral classification standards globally. By tightening criteria around hydration status, diffraction verification, and community input, the commission has laid out a framework designed to support both academic research and practical applications across geology, gemology, and materials science. Readers interested in detailed case studies may consult the full European Journal of Mineralogy article, volume 38, pages 629–633 (2026) ¹.