Whiterockite, CaMgMn3+3O2(PO4)2CO3F·5H2O, is a new phosphate–carbonate mineral from the White Rock No. 2 quarry, Bimbowrie Conservation Park, South Australia, Australia. The mineral is associated with dufrénite/natrodufrénite, ushkovite, bermanite, leucophosphite and sellaite in a matrix comprising fluorapatite and minor quartz. Whiterockite has formed from hydrothermal alteration and weathering in an oxidising, low-temperature and low-pH environment. Whiterockite forms aggregates of thin platy dark-red crystals up to 0.7 mm across with individual crystals up to 0.2 mm in across. Crystals are transparent with a vitreous lustre. The mineral is brittle, has a perfect cleavage on {001} and has an irregular fracture. The measured density is 2.76(2) g/cm–3. Whiterockite is optically biaxial (–), with α = 1.660(3), β = 1.760(5) and γ = 1.770(5), determined in white light; 2Vmeas = 30(1)°; and orientation: X ≈ c*. The mineral is pleochroic: shades of red brown; X < Y < Z. Electron microprobe analyses provided the empirical formula (Ca0.87Na0.18)Σ1.05Mg1.05(Mn3+2.87Fe3+0.10)Σ2.97O1.93(PO4)2.01CO3F1.04·4.99H2O. Whiterockite is monoclinic, C2/m, a = 11.112(2), b = 6.4551(13), c = 10.667(2) Å, β = 102.61(3)º, V = 746.7(3)Å3 and Z = 2. The crystal structure of whiterockite has been refined using single-crystal synchrotron X-ray diffraction data to R1 = 5.10% on the basis of 957 reflections with F0 > 4σ(F0). The structure can be described as a layered structure formed by the stacking along [001] of three kinds of layers and is related to the structure of jörgkellerite.

The new mineral steiningerite, ideally Ba2Zr2(Si4O12)O2, was discovered along fissures and in cavities in melilite nephelinite samples retrieved from the currently active Löhley quarry, Eifel Volcanic Fields, Germany. Steiningerite is associated with minerals of the pyroxene group (augite–diopside), leucite, perovskite, titanite and accessory fluorapatite, fresnoite, wöhlerite, götzenite, fersmanite, magnetite and minerals of the pyrochlore group. It usually forms colourless or creamy white, euhedral, short prismatic to thick tabular, partly pseudocubic crystals up to 100 μm in size but also occurs rarely as individuals reaching 0.5 mm in size. The mineral is transparent to translucent, exhibits a vitreous lustre and no visible cleavage. The calculated density of steiningerite is 3.78 g/cm3. Optically, steiningerite is non-pleochroic and uniaxial (+), with ω = 1.711(3) and ε = 1.750(3) (λ = 589 nm). The empirical formula of holotype steiningerite, calculated on 14 anions, is (Ba1.36K0.56Na0.09Sr0.05Ca0.02)Σ2.08(Zr1.52Ti0.25Nb0.13U0.05Fe0.02Hf0.01)Σ1.98(Si4.00Al0.03)Σ4.03O12(O1.59F0.41)Σ2.00. Steiningerite crystallises in space group P4/mbm, with refined unit-cell parameters a = 8.894(2) Å, c = 8.051(2) Å, V = 636.9(3) Å3 and Z = 2. The crystal structure, determined from single-crystal intensity data, was refined to R = 0.0310 for 444 unique reflections with I > 3σ(I). The mineral is isotypic with the synthetic KTaSi2O7 and structurally similar to the mineral rippite, K2(Nb,Ti)2(Si4O12)(O,F)2. The hetero-polyhedral framework is formed by the chains of (Zr,Ti)O6 octahedra, running parallel to the four-fold axis, which are combined via Si4O12 rings. Each (Zr,Ti)O6 octahedron shares four vertices with four SiO4 tetrahedra, belonging to four different Si4O12 units. This arrangement of atoms creates channels along the c axis, with a pentagonal cross-section, in which charge-balancing Ba2+ and K+ ions are located. Extra-framework alkaline and alkaline-earth cations have twelve-fold coordination. The occurrence of the new mineral in a melilite nephelinite, along with its high-temperature mineral association and the absence of H2O and OH groups, confirmed by Raman and FTIR spectroscopies, indicate high-temperature conditions of formation and suggests a pneumatolytic origin of steiningerite.

Phosphide-bearing diopside–anorthite paralava found in the distribution area of the pyrometamorphic rocks of the Hatrurim Complex in Jordan (Daba-Siwaqa field) and Israel (Hatrurim Basin field) have yielded a large number of new phosphides and phosphates. In 2019, a small outcrop of phosphide-bearing breccia with cement composed of gehlenite–flamite paralava was discovered in the Hatrurim Basin. A new pyrophosphate, yamhamelachite, KCrP2O7 (P21/c, a = 7.3574(3), b = 9.9336(4), c = 8.1540(4) Å, β = 106.712(5)°, V = 570.77(5) Å3 and Z = 4), occurs at the phosphide-enriched boundary between an altered sedimentary xenolith and the gehlenite–flamite paralava. Yamhamelachite forms green aggregates in which the size of grains does not exceed 25–30 μm. The mineral is transparent with a glassy lustre. Yamhamelachite is brittle with conchoidal fracture. Mohs hardness = 4. The empirical formula of yamhamelachite calculated on the basis of average microprobe analyses is (K0.89Ca0.01□0.10)Σ1.00 Cr3+0.50V3+0.33Al0.15Fe3+0.04 Ti4+0.03)Σ1.05P1.98O7. The density calculated from the empirical formula and structural data is 3.035 g·cm–3. Cr3+ in yamhamelachite is substituted by V3+, and in a few cases V is marginally more abundant than Cr, indicating the presence of a potentially new mineral with the formula KVP2O7. Yamhamelachite consists of layers of Cr3+-octahedra and pyrophosphate groups connected at their apices, and potassium located within channels parallel to [001]. A characteristic feature of phosphide aggregates associated with yamhamelachite is the presence of two generations of barringerite, the earlier of which has higher Cr and V content. In the general crystallisation sequence, yamhamelachite appears after phosphides (+pyrrhotite and daubréelite) and then spinels of the chromite–magnetite series crystallise, along with ferromerrillite and ferroalluaudite. The source of chromium for yamhamelachite was mainly V–Cr-bearing pyrrhotite and V-bearing daubréelite. The low Fe3+ content in yamhamelachite, probably related to its late-stage alteration, indicates that it crystallised from phosphate melt under reducing conditions at ∼1000°С.

Anorthoyttrialite-(Y) occurs as inclusions in yttrian fluorite from the Stetind pegmatite, Narvik, Nordland, Norway, associated with allanite-(Ce), alnaperbøeite-(Ce), bastnäsite-(Ce), fluorite, hematite, hundholmenite-(Y), perbøeite-(Ce), rowlandite-(Y), schlüterite-(Y), synchysite-(Y), thalénite-(Y), törnebohmite-(Ce) and vyuntspakhkite-(Y). It forms translucent tabular or needle shaped crystals, which are colourless or white, yellow or brownish. It is optically biaxial (–) with α = 1.705(1), β = 1.750(1), γ = 1.756(2) and 2Vcalc = 39.09°. The calculated and measured density is 5.24 g·cm–3 and 5.1 g·cm–3 respectively. The empirical formula of anorthoyttrialite-(Y) based on 14 oxygen atoms per formula unit is (Y1.561La0.033Ce0.242Pr0.059Nd0.367Sm0.177Gd0.298Tb0.036Dy0.297Ho0.058Er0.258Tm0.071Yb0.385Lu0.041Ca0.099Mn0.029U0.003Th0.01)Σ4.024Si4.011O14.

Two polytypic crystal structures have been determined in triclinic space group $P\bar 1$. Anorthoyttrialite-(Y)-1A is isostructural with the B-type structure known for synthetic rare earth element disilicates of composition REE2Si2O7, where REE = Y, Eu, Gd, Tb, Dy, Ho, Er, Tm. Unit cell parameters are a = 6.6107(4), b = 6.7139(3), c = 12.2034(9) Å, α = 94.819(3), β = 90.583(3), γ = 91.742(3)° and V = 539.42(5) Å3 with Z = 2. The five strongest lines in the calculated powder diffraction pattern are (d in Å (I) hkl) as follows: 4.369 (72) $1\bar 1\bar 1$, 3.040 (100) 004, 3.040 (71) $02\bar 2$, 2.918 (68) $\bar 202$, 2.814 (59) 211. Anorthoyttrialite-(Y)-2A has unit cell parameters a = 6.6068(6), b = 6.7147(6), c = 24.218(2) Å, α = 94.435(6), β = 90.315(5), γ = 92.092(5)°, V = 1070.41(16) Å3 and Z = 4. The five strongest lines in the calculated powder diffraction pattern are: 4.378 (75) $1\bar 1\bar 2$, 3.027 (79) $0\bar 24$, 3.018 (100) 008, 2.907 (68) $\bar 204$, 2.810 (59) 212. Both polytypes contain linear trisilicate anion groups [Si3O10]8– as well as isolated [SiO4]4– tetrahedra, while the REE are six-, eight-, and nine-coordinated by oxygen. The crystal structures consist of essentially two types of layers with different stacking order. Similar layer stacking is discussed in relation to other rare earth disilicates like percleveite-(Ce) and thortveitite. Anorthoyttrialite-(Y) is also compared to a heat treated metamict Y-silicate from Stetind.

The rare Pb silicate jagoite, known only from the Långban and Pajsberg Mn–Fe oxide deposits in Värmland, Sweden, is associated with a more diverse mineral assemblage than originally described: alamosite, barysilite, hyttsjöite, margarosanite, melanotekite, nasonite and yangite and other, not fully characterised Pb silicates. Primary melanotekite and barysilite, formed as skarn (together with hematite, quartz, clinopyroxene and andradite) during regional metamorphism, are prone to alteration, with Cl⁻, SiO₂, Ca2⁺ and H₂O acting as modifying agents. In the process, newly formed Pb silicates exhibit increasing Si content, reflecting a higher degree of SiO₄ polymerisation at high pH and decreasing temperatures.

A refinement of the crystal structure of jagoite from X-ray diffraction data, to R1 = 1.2% [space group P$\bar 6$2c, a = 8.53926(5) Å and c = 33.3399(2) Å], confirms previous work, and provides significantly improved structural parameters. New data were also obtained with Mössbauer spectroscopy, laser-Raman micro-spectroscopy, electron-microprobe and laser-ablation inductively coupled plasma mass spectrometry analyses. The results indicate that jagoite accommodates minor elements, notably Al at an octahedrally coordinated Fe-dominated site and Mn3⁺, Zn and Mg at four-coordinated mixed Fe–Si sites, and small amounts of Ca+Na replacing Pb. Jagoite is also enriched in Be, Sb, Bi and Br, but those elements have a limited role in its crystal chemistry. Mössbauer measurements show that Fe3⁺ is distributed over three different crystallographic sites, two 4-coordinated and one 6-coordinated, and that jagoite remains paramagnetic down to 77 K. The ideal chemical formula for jagoite should be written Pb11Fe5Si12O41Cl3 for Z = 2.

Marsaalamite-(Y), ideally Y(MoO4)OH, is a new molybdate mineral discovered in the greisenised Um Safi F-rich granite located in the Marsa Alam District, Central Eastern Desert, Egypt. It typically occurs as inclusions in or intergrowths with F-rich zinnwaldite. It forms micaceous aggregates, with sizes varying from 0.1 to 1 mm. Marsaalamite-(Y) is non-magnetic, white in colour, and has an earthy lustre and white streak. It is brittle (3–4 Mohs) and has basal cleavages {010}. The calculated density is 4.90 g.cm–3 based on the empirical formula and unit-cell parameters refined from powder X-ray diffraction data. Marsaalamite-(Y) is associated with arsenopyrite, baryte, bastnäsite-(Ce), cassiterite, chernovite-(Y), columbite-(Fe), fluocerite-(Ce), fluorite, iron oxy-hydroxides, löllingite, molybdenite, monazite-(Ce), pyrite, quartz, rutile, thorite, wolframite, wulfenite, xenotime-(Y) and several unidentified phases. The empirical formula is (Y0.67Er0.10Dy0.08Yb0.08Ho0.02Lu0.02Tm0.02Ca0.01)Σ1.00(Mo0.95S0.03As0.01P0.01)Σ1.00O4.00[(OH)0.88F0.11Cl0.01]Σ1.00; the ideal end-member formula is Y(MoO4)(OH). The presence of a hydroxyl group has been confirmed by Raman and infrared spectroscopy, and its concentration has been calculated from the stoichiometry. Marsaalamite-(Y) is the natural (OH)-dominant analogue of synthetic Y(MoO4)F. It is monoclinic, space group P21/c, with unit-cell parameters a = 5.1863(7) Å, b = 12.3203(11) Å, c = 6.6953(7) Å, β = 114.173(8)°, V = 390.30(8) Å3, and Z = 4. Extreme fractionation of the parental halogen-rich, A-type granitic magma triggered the greisenisation of the granite. Marsaalamite-(Y) occurred simultaneously with or immediately after the crystallisation of F-rich zinnwaldite based on the textural relationship. Therefore, the crystallisation of marsaalamite-(Y) was most likely to have been controlled by fluid-induced processes rather than magmatic conditions. The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2024-050) and named after the Marsa Alam District, Al-Bahr Al-Ahmer Governorate, Egypt.

Manuelarossiite, ideally CaPbAlF7, is a new fluoride mineral found in a specimen from a fumarole formed subsequent to the 1944 eruption of the Vesuvius volcano, Naples Province, Campania, Italy. It occurs as very rare tabular crystals, up to 0.06 × 0.04 × 0.015 mm, in the vugs of volcanic scoria, associated with cerussite. In the same scoria where manuelarossiite was found, anglesite, artroeite, atacamite, calcioaravaipaite, cerussite, challacolloite, cotunnite, hephaistosite, matlockite, napoliite and susannite were identified. Manuelarossiite is colourless with a white streak and adamantine lustre. It is brittle and has a laminated fracture. Cleavage is perfect on {001}. Dcalc = 5.095 g cm–3. The calculated mean refractive index is 1.625. The chemical composition (wt.%, electron microprobe, H2O calculated by stoichiometry) is: CaO 13.98, PbO 55.46, Al2O3 12.59, F 29.45, H2O 1.68, –O=F –12.40, total 100.76. The empirical formula calculated on the basis of 7 anions is Ca1.00Pb1.00Al1.00[F6.25(OH)0.75]Σ7.00. Raman spectroscopy confirms the limited presence of OH– groups in the mineral. Manuelarossiite is monoclinic, space group C2/m, with a = 7.6754(3), b = 7.4443(4), c = 9.2870(5) Å, β = 93.928(5)°, V = 529.39(5) Å3 and Z = 4. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 9.257 (57) (001); 4.537 (72) (111); 3.725 (98) (020); 3.630 (57) (20$\bar 1$); 3.588 (65) (11$\bar 2$); 3.460 (100) (021); 3.422 (63) (112); and 2.673 (65) (220). The crystal structure was refined to R1 = 0.056 for 849 reflections with F > 4σ(F). It is characterised by {001} layers formed by CaF8 polyhedra decorated on both sides by AlF6 octahedra, in turn connected to the {001} layer through edge-sharing. Successive {001} layers are bonded through Pb atoms. The new mineral honours Dr. Manuela Rossi (b. 1977) from the University of Naples for her contribution to the study of the Vesuvius volcano and its minerals.

Chalcedony forms across a wide area in eastern Iran, particularly in the Sarbisheh district near Birjand city, with notable occurrences in the Qazdez-Bahamarz region. Here, cryptocrystalline quartz is found in hydrothermal veins and veinlets within volcanic rocks hosted by carbonate and intermediate igneous formations. Chalcedony samples of various colours—black, purple, green, blue, lavender, grey, lemon yellow and white—were analysed using diverse techniques. These chalcedony samples display fibrous and granular textures, comprising microcrystalline quartz, cryptocrystalline moganite, and opal-CT and opal-C interlayers. Elements that affect the colouration of chalcedony include iron (producing red and yellow tones), chromium (green), manganese (black, blue and grey patterns), nickel (purple) and copper (also purple). Altered carbonate host rocks are enriched in Fe, Cu, Zn and Cd, with Al and Mn depletion. Stable isotope analyses show δ18O values in agates range from +14.9‰ to +25.5‰, whereas δ18O and δ13C values in carbonate minerals and chalcedony range from +14.1‰ to +24.8‰ and –5.7‰ to +0.7‰, indicating agate formation from mantle-derived hydrothermal fluids mixed with meteoric waters. Raman spectroscopy detected moganite, α-quartz, goethite, aragonite and illite in agate interlayers. Analyses by field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) revealed minerals of Fe, Cr, Ni, Ti and Sn. X-ray diffraction confirmed chalcedony, moganite and opal-CT, whereas EPR spectroscopy showed strong magnetic backgrounds from goethite and silicon-vacancy centres formed by radioactive decay of U, Th and their byproducts.

The new mineral pabellóndepicaite (IMA2023-104), Cu2+2(N3C2H2)2(NH3)2(NO3)Cl·2H2O, was found in the guano deposit at Pabellón de Pica, Iquique Province, Chile, where it is a secondary phase formed at the contact between an altered guano deposit and a chalcopyrite-bearing gabbro. Pabellóndepicaite occurs on salammoniac in association with antipinite, bojarite, dittmarite, halite, joanneumite, sampleite, struvite, wheatleyite and whewellite. Crystals are rectangular blades or tablets, up to ∼0.2 mm long, flattened on {001} and elongated along [100] and exhibiting the forms {010}, {001}, {011} and {102}. Crystals are indigo blue and transparent, with vitreous lustre and light indigo blue streak. The mineral is brittle with curved and stepped fracture. The Mohs hardness is ∼2½. Cleavage is perfect on {001} and good on {010}. The density is 1.95(2) g·cm–3. Optically, pabellóndepicaite is biaxial (+) with α = 1.583(3), β = 1.596(3) and γ = 1.644(3) (white light). The 2V is 56(2)° with distinct r > v dispersion. The optical orientation is X = a, Y = b, Z = c and the pleochroism is X light indigo blue, Y indigo blue, Z pale indigo blue; Y > X > Z. The empirical formula is Cu2Cl1.25N9C4H13.75O4.75 (with H, C and N calculated based on the structure). Pabellóndepicaite is orthorhombic, space group Pmma, with cell parameters: a = 7.2118(12), b = 9.0983(15), c = 11.128(3) Å, V = 730.2(2) Å3 and Z = 2. The structure (R1 = 6.65% for 482 I > 2σI reflections) contains two types of polyhedral chains (1) a zig-zag chain of CuN4Cl2 octahedra linked by sharing Cl atoms and the N–N edges of 1,2,4-triazolate groups and (2) a chain of CuN4O2 octahedra alternating with NO3 triangles. The chains are linked to one another by 1,2,4-triazolate groups to form layers with isolated H2O groups in their cavities.

Elaborately zoned blue–grey tourmaline from the Dorothy China Clay Pit, St. Austell, Cornwall, UK reveals a history of hydrothermal activity in an open system. At least five distinct generations of tourmaline are identified within a single crystal. They are characterised by complex replacement textures displaying dissolution and reprecipitation features and compositional variations identified using optical microscopy, BSE-imaging and EPMA. The Li-rich, alkali-poor rossmanite core of the grain is considered as generation 1 tourmaline. Generation 2 tourmaline comprises a more Na-rich species, especially elbaite. Generation 3, partially replacing the core, is richer in Fe, and is mostly schorl and foitite. Generation 4, primarily Fe-rich dravite, forms an Mg-enriched rim around generations 1–3. Generation 5 fluor-schorl replaces all previous tourmaline generations and parts of the quartz matrix. Each generation corresponds to a chemically distinct fluid event suggested by dissolution textures and compositionally differing overgrowths. Infiltration of B-bearing, neutral-to-acidic fluids facilitated the growth of tourmaline. These fluids contained varying amounts of major elements reflected in the changing tourmaline composition. Dissolution probably occurred because of an increase in fluid pH or a change in major cation abundances. Generation 1 tourmaline crystallised in equilibrium with a Li-rich, Na-poor granitic host rock. From generations 1 to 3, fluids generally increased in Na and Fe while decreasing in Al and Li. Fluids increased in F at generation 3, followed by the influx of more oxidising, Mg-enriched fluids at generation 4. The final generation 5 represents a return to compositions richer in Fe and F. The episodic changes in fluid composition preserved by each generation of tourmaline records fluid infiltration. These differing compositions might reflect, in part, progression of kaolinisation of the host granites or changes in the magmatic–hydrothermal fluids. The St. Austell kaolinite deposits formed from hydrothermal alteration of the preexisting granite through multiple stages of reactive fluid infiltration as recorded in tourmaline.

Gorbunovite, CsLi2(Ti,Fe+3)(Si4O10)(F,OH,O)2, a new caesium trioctahedral mica, was discovered in the Darai-Pioz alkaline massif, Tajikistan. The mineral is named after the Russian chemist, leader of the Tajik-Pamir Expedition, Academician Nikolai Petrovich Gorbunov (1892–1938). Gorbunovite occurs as lamellar grains or flakes from 2 μm to 0.2 mm in a quartz–pectolite aggregate and is associated with quartz, fluorite, pectolite, baratovite, aegirine, leucosphenite, neptunite, reedmergnerite, orlovite, sokolovaite, mendeleevite-(Ce), odigitriaite, pekovite, zeravshanite, kirchhoffite and garmite. The mineral is colourless, transparent, with vitreous lustre. Mohs hardness is 2½. Dmeas. is 3.28 (2), Dcalc is 3.302 g/cm3. Gorbunovite is optically biaxial (–), α = 1.609(2), β = 1.621(2), γ = 1.623(2), 2Vmeas. 30(5) and 2Vcalc. 44. Gorbunovite is monoclinic, space group C2/m, C2 or Cm (polytype 1M), a = 5.236(2), b = 9.054(4), c = 10.767(4) Å, β = 99.61(4)°, V = 503.3(6) Å3 and Z = 2. The strongest lines in the powder X-ray diffraction pattern [d, Å, (I)] are: 4.49 (25), 3.94 (20), 3.69 (46), 3.57 (23), 3.45(34), 2.991 (42), 2.608 (77), 2.581 (100), 2.240 (33), 2.188 (62), 2.020 (24), 1.722 (27) and 1.511 (23). Chemical composition (microprobe analysis; H2O, Li2O – SIMS) is: SiO2 47.44, TiO2 9.40, Al2O3 0.66, MgO 0.63, Fe2O3 3.64, ZnO 1.01, K2O 0.39, Cs2O 26.64, Li2O 5.83, H2O 0.89, F 4.48, –O=F 1.89, total 99.17. The empirical formula is (Cs0.96K0.04)Σ1.00Li1.98(Ti0.60Fe+30.23Mg0.08Al0.07Zn0.06)Σ1.04Si4.00O10(F1.19OH0.50O0.31)Σ2.

The new mineral natromolybdite, ideally Na2MoO4·2H2O, was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. The associated minerals are halite, sylvite, aphthitalite, belomarinaite, powellite, hematite, sanidine, tilasite, johillerite, bradaczekite, badalovite, arsmirandite, wrightite, arsenatrotitanite, dmisokolovite, litidionite, rutile and cristobalite. Natromolybdite occurs as rectangular, octagonal or rhomb-like lamellar to thin-tabular crystals up to 40 μm across and up to 3 μm thick, in near-parallel, pile-like or rose-like aggregates and crystal crusts up to 0.2 mm across. It is transparent and colourless, with vitreous lustre. Dcalc is 2.573 g/cm3. The synthetic analogue of natromolybdite is optically biaxial (+), α = 1.575(2), β = 1.576(2), γ = 1.598(3) and 2Vmeas = 20(10)°. The chemical composition (wt.%, electron microprobe, H2O is calculated by stoichiometry) is: Na2O 25.51, K2O 0.66, SO3 1.04, MoO3 58.21, H2Ocalc 15.05, total 100.47. The empirical formula, calculated based on O = 6 apfu, is (Na1.971K0.034)Σ2.005(Mo0.968S0.031)Σ0.999O4·2H2O. Natromolybdite is orthorhombic, space group Pbca, a = 8.483(1), b = 10.577(2), c = 13.842(2) Å, V = 1242.0(2) Å3 and Z = 8. The nine strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 6.92(100)(002), 4.243(20)(200), 4.206(32)(022), 3.618(31)(202), 3.310(31)(220), 3.169(49)(131), 3.067(21)(114), 2.987(30)(222) and 2.681(15)(204, 311). Natromolybdite (IMA-accepted symbol Nmyb) is named for the chemical composition. It is a natural analogue of a well-studied synthetic sodium molybdate dihydrate.