The formal approval of a new mineral species by the International Mineralogical Association is never a single event but the culmination of a layered process, and Newsletter 93 of the Commission on New Minerals, Nomenclature and Classification offers a useful window into how that process operates in practice. Each proposal listed in the newsletter carries an IMA number that encodes the year of submission and a sequential identifier, sometimes with letter suffixes such as the c in IMA 2023-077c, which signals that earlier versions of the same proposal were returned to the authors for revision before final acceptance. This iterative character is a deliberate feature of the system: the commission’s reviewers, who examine chemical analyses, crystallographic data, and the description of the type specimen, can request additional measurements or clarifications, and only when the proposal satisfies the commission’s standards does it receive a status that permits publication of the summary data ahead of the full description.

The distinction between approval and full description is worth emphasizing for readers unfamiliar with mineralogical practice. When the commission approves a species, the newsletter publishes a standardized set of data: the name, the ideal formula, a two- or three-letter symbol, the type locality, the authorship of the proposal, the crystal system and space group, unit-cell parameters, the strongest lines of the X-ray powder diffraction pattern, and the repository holding the type material. What the newsletter deliberately withholds is any interpretive narrative. The commission’s stated policy is that no information beyond these essentials will be released, and the proposing authors remain obligated to publish a complete description of the mineral, including its occurrence, paragenesis, physical properties, optical behavior, and the analytical details underpinning the formula, in a peer-reviewed venue. This two-stage arrangement protects the priority of the discoverers while ensuring that the mineralogical community receives the essential identifiers quickly and in a uniform format that can be added month by month to the commission’s public database.

The type specimen itself is the anchor of the entire system. Every approved species in this newsletter is accompanied by a designated repository and catalogue number, whether that is the Museo di Scienze della Terra in Bari, the National Geological Museum of China in Beijing, the Natural History Museum of Los Angeles County, the Carnegie Museum of Natural History in Pittsburgh, the National Museum of Nature and Science in Tsukuba, the Bavarian State Mineral Collection in Munich, or the Muséum Cantonal des Sciences Naturelles in Lausanne. The type material is the physical reference against which all future identifications of the species are measured. Where a proposal lists both a holotype and a cotype, or several cotype specimens distributed among institutions, this reflects cases where the available material was divided or where different portions of the collection carry complementary analytical value. The practice of depositing type material in publicly accessible collections is one of the quiet strengths of mineralogical nomenclature, because it means that disputes about the identity of a species can, in principle, be resolved by direct examination of the original grains decades or centuries later.

Several of the newly approved species illustrate how modern mineral discovery increasingly depends on analytical techniques capable of interrogating very small volumes of material. Proxicosahedrite, found in a micro-spherule of a micrometeorite collected on Mount Gariglione in Calabria, Italy, is a case in point. Its formula, Al52Cu30Fe11Si7, and its cubic structure with a unit-cell edge of about 12.34 Å identify it as a member of the family of complex metallic alloys whose synthetic analogues have long been studied for their unusual quasiperiodic and approximant structures. The discovery of such phases in extraterrestrial material continues a line of research in which natural samples, often formed under transient high-energy conditions during atmospheric entry or impact, are found to reproduce structures first encountered in the laboratory. The prefix prox- in the name alludes to this proximity to the related cosahedrite-type arrangement, and the determination of the structure from a spherule only micrometers across required electron diffraction methods rather than conventional single-crystal X-ray work, a technique that has become routine in the characterization of sub-millimeter mineral grains.

Wusiheite, by contrast, comes from a very different geological setting: the Wusihe lead-zinc deposit in Sichuan Province, China. Its formula, BaGe(Ge3O9), places it in the benitoite group, and the newsletter explicitly identifies it as the Ge-Ge analogue of benitoite itself, the famous barium titanium silicate that serves as the state gemstone of California. Benitoite-type structures consist of rings of corner-sharing tetrahedra arranged in trigonal symmetry, and the substitution of germanium for silicon and titanium in these tetrahedral sites produces a mineral whose framework is topologically identical to benitoite but chemically distinct. Germanium minerals are rare in nature because germanium is a trace element in most crustal rocks, concentrating only in specific settings such as oxidized sulfide deposits, and each new natural germanate therefore adds to a small but scientifically valuable inventory of phases that probe the crystal-chemical behavior of germanium at high valence states.

Bromammoniac, the bromine analogue of salammoniac, is another example of a species whose significance lies less in its complexity than in the environment that produced it. Ammonium halides are among the most chemically simple minerals known, and salammoniac itself has been recognized for centuries, often forming as sublimates around volcanic fumaroles and burning coal seams. The new bromide phase was recovered from an active vent in burning bituminous shale of the Monterey Formation on a sea-cliff talus slope along the Pacific coast at Hope Ranch, Santa Barbara, California. Spontaneous combustion of organic-rich shale generates a low-temperature but chemically aggressive environment in which volatile components, including ammonia and hydrogen bromide derived from the burning organic matter and saline fluids, combine and crystallize as the gases cool. Such combustion metamorphic settings are ephemeral, often lasting only years or decades, and minerals from them are correspondingly rare in the literature, which makes their formal documentation all the more important for understanding the full range of conditions under which crystalline phases can form naturally.

Usagreite, from the Mariquita mine in Badajoz Province, Spain, belongs to a different chemical world altogether. Its formula, Hg2+2S2, and its monoclinic structure place it among the mercury sulfatosalts, a family of compounds in which mercury-sulfur bonds coexist with sulfate groups. The newsletter describes it as the sulfate analogue of alexearlite, and the structural determination confirms that the mercury-sulfur framework persists while the anion chemistry changes. Mercury minerals of this kind typically form in the supergene oxidation zone of mercury deposits, where cinnabar and other primary sulfides are weathered and the resulting mercury is redistributed into secondary phases. The Mariquita mine, in the Extremadura region, is one of the historic mercury mining districts of the Iberian Peninsula, and the discovery of a new species there underscores how even long-worked localities can still yield minerals unknown to science when modern analytical methods are applied to old collections or to freshly exposed oxidation zones.

Aluminomacfallite, from the Kokuriki mine in Hokkaido, Japan, extends a different branch of nomenclature. The suffix -macfallite refers to an existing species, and the prefix aluminomarks the new mineral as its aluminium analogue, in which aluminium replaces the trivalent cation of the parent species in the sorosilicate framework defined by the (SiO4)(Si2O7) groups. The systematic naming of analogues in this way is governed by strict IMA rules: an analogue differs from its parent species only in the dominant occupancy of one or more crystallographic sites, and the prefix must unambiguously identify the substituting element. This convention allows the mineralogical literature to grow in a controlled way, with each new analogue occupying a predictable position in a chemical series rather than requiring an entirely new root name.

Lincioite, from the Lagoscuro mine in Liguria, Italy, is assigned to the hydrotalcite supergroup, a large family of layered double hydroxides characterized by positively charged brucite-like layers interleaved with anions and water molecules. The formula of lincioite, Ni2+Fe3+O2(OH)10·3H2O, shows the characteristic alternation of divalent and trivalent cations in the layers with carbonate occupying the interlayer, and its trigonal R3m symmetry with a basal spacing of about 22.4 Å is typical of the group. Layered double hydroxides are of considerable interest beyond mineralogy because of their anion-exchange properties and their use as catalyst precursors and corrosion inhibitors, and natural occurrences such as lincioite, formed in the oxidation zone of a serpentinite-hosted ore deposit, provide reference points for understanding how these synthetic materials weather and transform over geological time.

Wolfgangpauliite, named for the physicist Wolfgang Pauli, is a uranyl phosphate from the Bois Noirs-Limouzat mine in the Forez massif of France, a locality known for its uranium mineralization. Its formula, Ca1.5K(H2O)5.5[(UO2)3O2(PO4)2], and its monoclinic C2/m structure relate it chemically and structurally to françoisite-(Ce), another uranyl phosphate with a similar sheet architecture. Uranyl phosphates form one of the most structurally diverse families of secondary minerals, arising wherever hexavalent uranium from primary ores migrates in oxidizing groundwater and encounters phosphate-bearing solutions. Their structures are built from uranyl pentagonal bipyramids linked by phosphate tetrahedra into sheets, with interlayer cations and water molecules occupying the space between. The diversity of this family, which now numbers well over a hundred species, reflects the flexibility of the uranyl-phosphate sheets and the variety of cations that can occupy the interlayer, and each new member refines the crystal-chemical systematics used to predict uranium mobility in contaminated environments.

Sainzbarandaite, from the Qinglong antimony deposit in Guizhou, China, is a calcium aluminium fluoride hydrate with the formula Ca7Al4F26(H2O)5, related to gearksutite and carlhintzeite. Fluoride minerals of this kind form in the near-surface alteration of fluorine-rich ore systems, and the Qinglong deposit, one of the world’s largest antimony producers, provides the chemical environment in which calcium, aluminium, and fluorine combine in unusual proportions. The large unit cell, with c close to 30 Å, indicates a complex layered structure, and the determination of that structure from such a rare phase demonstrates the power of modern single-crystal methods even when only minute crystals are available.

Finally, rozhdestvenskayaite-(Fe), from the Bianjiadayuan deposit in the Great Hinggan Range of China, belongs to the sulfosalt group, a family of phases built from packed metal-sulfur frameworks in which silver, antimony, and iron combine in complex stoichiometries. The Levinson-style suffix -(Fe) indicates the dominant trivalent cation in the formula, following the convention used for rare-earth and other variable-valence minerals. Sulfosalts are among the most structurally intricate of all minerals, and the revision of their nomenclature over recent decades has been one of the commission’s major undertakings, with entire subcommittees devoted to reconciling old names with new structural data. The approval of a new sulfosalt species therefore carries implications beyond the single mineral, contributing to a systematic framework that underpins the classification of ore deposits and the interpretation of their genesis.

Taken together, the eleven approvals in this newsletter span nearly the whole breadth of mineralogical interest: an extraterrestrial metallic alloy, a germanate from a sulfide deposit, a combustion sublimate, a mercury sulfatosalt, a sorosilicate analogue, a layered double hydroxide, a uranyl phosphate, a fluoride, and a sulfosalt. They also span the globe, from Calabria to Hokkaido, from Sichuan to Extremadura, from Liguria to the Forez massif, and from Santa Barbara to Inner Mongolia. That breadth is not accidental. The commission’s monthly newsletters function as a running census of the mineral kingdom, and each entry, however terse, records a moment at which a new arrangement of atoms was recognized, verified, named, and committed to the permanent record of science.

Subject of Research: …

Article Title: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 93

Article References: Bosi, F., Hatert, F., Pasero, M., & Mills, S. J. (2026). IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 93. European Journal of Mineralogy, 38(5), 629-633. https://doi.org/10.5194/ejm-38-629-2026

Image Credits: AI Generated

DOI: 10.5194/ejm-38-629-2026

Keywords: mineralogy, IMA, new minerals, CNMNC, crystallography, micrometeorite, quasicrystal, uranium minerals, tetrahedrite, benitoite, X-ray diffraction, mineral nomenclature