Rietveldite (IMA2016-081), Fe(UO 2)(SO 4) 2 •5H 2 O, is a new uranyl sulfate mineral described from three localities: Giveaway-Simplot mine (Utah, USA), Willi Agatz mine (Saxony, Germany) and Jáchymov (Western Bohemia, Czech Republic). The mineral rarely occurs in blades up to 0.5 mm long, in association with other post-mining supergene uranyl sulfates and U-free sulfates. Rietveldite is orthorhombic, space group Pmn2 1 , a = 12.9577(9), b = 8.3183(3), c = 11.2971(5) Å, V = 1217.7(1) Å 3 and Z = 4. Thin blades are elongated on [001] and flattened on {010}. Rietveldite is brownish yellow; powdery aggregates have yellowish beige color; and it has a white streak. It does not exhibit fluorescence under either long-or shortwave UV. It is transparent to translucent with a vitreous luster. Crystals are brittle, with curved fracture and Mohs hardness ~2. Cleavage is good on {010}, and fair on {100} and {001}. Rietveldite is easily soluble in room-temperature H 2 O. The density is 3.31 g/cm 3. Rietveldite is optically biaxial (+), with α = 1.570(1), β = 1.577(1) and γ = 1.586(1) (white light); 2V calc. = 83.3°, 2V meas. = 82(1)°. Dispersion is very strong (r > v). Rietveldite exhibits barely noticeable pleochroism in shades of light brownish yellow color, Y < X ≈ Z. The optical orientation is X = b, Y = a, Z = c. Chemical analyses for rietveldite from Giveaway-Simplot (WDS, 4 spots on 2 crystals) provided FeO 9.56, ZnO 1.06, MgO 0.14, MnO 0.10, SO 3 26.99, UO 3 47.32, H 2 O (calc.) 15.39, total 100.56 wt. %, which yields the empirical formula (Fe 0.79 Zn 0.08 Mg 0.02 Mn 0.01) Σ0.90 (UO 2) 0.99 (SO 4) 2.01 •5.10H 2 O (based on 15 O apfu). Prominent features in the Raman and infrared spectra include the O-H stretching vibrations, symmetric and antisymmetric stretching vibrations of (UO 2) 2+ ion, and stretching and bending vibrations of symmetrically non-equivalent (SO 4) 2-groups. The eight strongest powder X-ray diffraction lines are [d obs Å (I rel.) (hkl)]: 8.309(34)(010), 6.477(100)(200), 5.110(58)(210), 4.668(48) (012), 4.653(36)(211), 3.428(41)(013), 3.341(33)(221), 3.238(49)(400). The crystal structure of rietveldite (R 1 = 0.037 for 2396 reflections with I obs > 2σ[I]) contains infinite uranyl sulfate chains of composition [(UO 2)(SO 4) 2 (H 2 O)] 2-along [001]. The adjacent chains are linked in the [100] direction by FeO 6 octahedra, which share vertices with SO 4 tetrahedra resulting in a heteropolyhedral sheet parallel to {010}; adjacent sheets are linked by hydrogen bonding only. The uranyl sulfate chains are the same as those in the structures of several other uranyl sulfate minerals. Rietveldite is named for Hugo M. Rietveld (1932-2016).

Plášilite (IMA 2014-021), Na(UO 2)(SO 4)(OH)•2H 2 O, is a new uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA. The new mineral occurs in and on sandstone matrix in close association with atacamite, blödite, brochantite, calcite, chalcanthite, dickite, gerhardtite, gypsum, hexahydrite, johannite, manganoblödite, natrozippeite and tamarugite. It is a low-temperature, secondary mineral formed by the post-mining weathering of uraninite. Plášilite is monoclinic, with the space group P2 1 /c, and unit cell parameters a = 8.7122(6), b = 13.8368(4), c = 7.0465(2) Å, β = 112.126(8)°, V = 786.89(7) Å 3 and Z = 4. Crystals are long, thin blades, elongated on [001] and flattened on {100}; rarely occur as prisms, also elongated on [001]. Crystals exhibit the forms {100}, {010} and {011}, and are commonly twinned on {100}. Plášilite is greenish yellow, has a white streak and fluoresces bluish white under both long-wave and shortwave UV. It is transparent with vitreous luster. The mineral has a Mohs hardness probably between 2 and 3, brittle tenacity, even fracture and two perfect cleavages, {010} and {001}. The calculated density based on the empirical formula is 3.726 g/cm 3. The mineral is optically biaxial (+), with α = 1.556(1), β = 1.581(1) and γ = 1.608(1) (measured with white light). The measured 2V is 88(1)° and the calculated 2V is 89°. Dispersion is moderate, r < v. The mineral is pleochroic with X = nearly colourless, Y = very pale yellow, Z = pale yellow; X < Y < Z. The optical orientation is X = b, Y ^ c = 4° in obtuse β. The empirical formula of plášilite is Na 0.94 (UO 2)(S 1.01 O 4)(OH)(H 2 O) 2 (based on 9 O apfu). Prominent features in the Raman spectrum include the symmetric stretching vibrations of the uranyl (UO 2 2+) group and sulfate tetrahedra and the O-H stretching and bending vibrations of the H 2 O molecules. The eight strongest powder X-ray diffraction lines are [d obs Å(I)(hkl) ]: 6.90(100)(020), 5.85(99)(011,111), 4.024(57)(200,130), 3.492(82) (102,220,040), 3.136(40)(122), 2.690(25)(141,102,241,032), 2.618(34)(240,150,302), 1.9212(30)(mult.). The crystal structure of plášilite (R 1 = 0.019 for 1603 reflections with F obs > 4σF) contains uranyl sulfate sheets of composition [(UO 2) 2 (SO 4) 2 (OH) 2 ] 2-parallel to (010). Between the sheets and linking them to one another are chains of edge-sharing NaO 2 (H 2 O) 4 octahedra parallel to [001]. The uranyl sulfate sheet is based on the phosphuranylite anion topology. The sheets in plášilite and deliensite are geometrical isomers.

The new mineral ammoniozippeite (IMA2017-017), (NH₄)₂[(UO₂)₂(SO₄)O₂]·H₂O, was found in both the Blue Lizard mine San Juan County, Utah, and the Burro mine, San Miguel County, Colorado, USA. At both mines, it occurs as a low-temperature, secondary phase. The mineral is yellow to yellowish orange with pale yellow streak and fluoresces dull green yellow under 405 nm laser light. Crystals are transparent and have vitreous luster. It is brittle, with Mohs hardness of about 2½, splintery fracture, and three cleavages: {010} and {001} perfect, {100} good. The calculated density for the ideal formula is 4.433 g/cm³. Crystals are acicular to bladed, elongate on [100], up to about 0.2 mm in length at the Blue Lizard, and up to 2 mm at the Burro. Ammoniozippeite is optically biaxial (+) with α = 1.678(2), β = 1.724(3), γ = 1.779(3) (white light); the measured 2V is 87.1(5)°; r < v dispersion is weak; the optical orientation is X = b, Y = c, Z = a; and pleochroism is X colorless, Y orange yellow, and Z yellow orange (X ≪ Y < Z). Electron microprobe analyses (WDS mode) provided the empirical formulae [(NH₄)_1.97Na_0.03]_Σ2.00(U_1.00O₂)₂(S_1.01O₄)O₂·H₂O and [(NH₄)_1.99K_0.06Na_0.04]_Σ2.09(U_1.01O₂)₂(S_0.97O₄)O₂·H₂O for crystals from the Burro and Blue Lizard mines, respectively. The five strongest X-ray powder diffraction lines for Burro mine material are [d_obs Å(I)(hkl)]: 7.17(100)(020), 3.580(21)(040), 3.489(42)(203), 3.138(63)(223), and 1.6966(18)(229,426). Ammoniozippeite is orthorhombic, Ccmb, a 8.7944(3), b 14.3296(7), c 17.1718(12) Å, V 2164.0(2) ų, and Z = 8. The structure of ammoniozippeite (R₁ = 0.0396 for 932 reflections with I_o > 2σI) contains edge-sharing zig-zag chains of pentagonal bipyramids that are linked by sharing corners with SO₄ groups, yielding a [(UO₂)₂(SO₄)O₂]^2– sheet based on the zippeite-type topology. The interlayer region contains two NH₄⁺ groups and one H₂O group pfu, statistically distributed over three sites.

Thorneite, Pb₆(Te₂⁶⁺O₁₀)(CO₃)Cl₂(H₂O), is a new tellurate from Otto Mountain near Baker, California, named in honor of Brent Thorne. The new mineral occurs on fracture surfaces and in small vugs in brecciated quartz veins. Thorneite is directly associated with acanthite, cerussite, gold, hessite, iodargyrite, khinite, wulfenite, and three other new tellurates: housleyite, markcooperite, and ottoite. Various other secondary minerals occur in the veins, including three other new secondary tellurium minerals: paratimroseite, telluroperite, and timroseite. Thorneite is monoclinic, space group C2/c, a = 21.305(1), b = 11.059(1), c = 7.564(1) Å, β = 101.112(4)°, V = 1748.8(4) ų, and Z = 4. Crystals are prismatic to bladed with elongation and striations parallel to c and typically occur in parallel and random aggregates. It is yellow and transparent, with pale yellow streak and adamantine luster. Mohs hardness is estimated at 2. The mineral is brittle, with an irregular to splintery fracture and good {100} cleavage. The calculated density is 6.828 g/cm³. Thorneite is biaxial (+), with large 2V, but indices of refraction are too high to be measured. The optic orientation is Y = b, Z ^ a = 29° in obtuse β. No pleochroism was observed. Electron microprobe analysis provided PbO 73.90, ZnO 0.03, TeO₃ 20.35, Cl 2.29, H₂O 1.28 (structure), CO₂ 2.29 (structure), O≡Cl −0.52, total 99.62 wt%; the empirical formula (based on O+Cl = 16) is (Pb_5.94Zn_0.01)(Te_2.08⁶⁺O₁₀)(C_1.00O₃)[Cl_1.16O_0.34(OH)_0.50](H₂O). The strongest powder X-ray diffraction lines are [d_obs in Å (hkl) I]: 10.43 (200) 35, 3.733 (5̅11, 2̅02, 002) 27, 3.595 (4̅21) 33, 3.351 (112) 66, 3.224 (511, 131) 100, 3.093 (2̅22, 3̅31) 30, 2.900 (6̅21) 44, 2.133 (821, 622, 223, 731, 242) 38. The crystal structure (R₁ = 0.028) contains edge-sharing octahedral tellurate dimers, [Te₂⁶⁺O₁₀]⁸⁻ that bond to Pb atoms, which in turn are linked via bonds to Cl atoms, CO₃ triangles, and H₂O molecules.