Jason B. Smith’s research while affiliated with University of North Carolina at Charlotte and other places

The new mineral siligiite, [Pb(H2O)5(SO4)][Zn9(OH)18] (IMA2023-117), was found in the Redmond mine, Haywood County, North Carolina, USA, where it occurs in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Siligiite was found in vugs in massive galena-sphalerite-chalcopyrite-quartz in close association with anglesite, bechererite, cherokeeite, cuprocherokeeite, elyite, kennygayite, leadhillite, and muscovite. Siligiite crystals are blades or flattened needles, up to about 1 mm long, with lengthwise striations, occurring in radiating clusters. The mineral is colorless with vitreous to silky luster. The mineral is brittle with splintery fracture and two cleavages: perfect on {001} and good on {100}. The Mohs hardness is about 2½. The calculated density is 3.513 g/cm3. The mineral is biaxial (+) with α = 1.624(3), β = 1.650(3), and γ = 1.656(3) (white light). The 2V is 50(2)° with distinct r > v dispersion. The optical orientation is Y = b,X ≈ c*, Z ≈ a. Electron probe microanalyses provided the empirical formula [Pb0.99(H2O)5(SO4)][(Zn8.81Cu0.19)Σ9.00(O0.9989H)18.02]. Siligiite is monoclinic, P21/n, a = 13.658(3), b = 9.488(3), c = 19.209(4) Å, β = 102.577(6)°, V = 2429.4(1) Å3, and Z = 4. The crystal structure of siligiite (R1 = 0.0576 for 5448 I > 2σI), contains a novel sheet comprised of Zn(OH)6 octahedra and Zn(OH)4 tetrahedra. A Pb2+ cation, an SO42− group, and several H2O groups are located between successive sheets.

The new mineral dinilawiite, [Pb4OAl(OH)6]2(S2O3)2·(S2O3)(H2O)5 (IMA2023-061), was found in the Redmond mine, Haywood County, North Carolina, USA, where it occurs in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Dinilawiite was found in vugs in massive galena-sphalerite-chalcopyrite-quartz in close association with hydroredmondite, steverustite, sulfatoredmondite, and susannite. Dinilawiite crystals are ubiquitously twinned tablets, up to about 0.4 mm across, with angled striations. Crystals always occur in tightly intergrown subparallel clusters. The mineral is colorless but sometimes appears light reddish brown due to inclusions or transmitted color of the matrix. The luster is vitreous. The mineral is brittle with curved fracture and no cleavage. The Mohs hardness is about 2. The calculated density is 4.727 g/cm3. The mineral is biaxial (+) with α = 1.805(5), β = 1.824 (calc), γ = 1.854 (calc) (white light). The 2V is 78(1)° with moderate r > v dispersion. The optical orientation is Z = b,Y^ c = 17° in the obtuse angle β and there is no pleochroism. Electron microprobe analyses provided the empirical formula [Pb4.00OAl1.00(OH)6]2(S2O3)2·(S2O3)0.60(SO4)0.28(OH)0.28(H2O)5.32. Dinilawiite is monoclinic, I2/a, a = 17.4100(5), b = 9.2191(2), c = 21.6980(15) Å, β = 107.276(8)°, V = 3325.5(3) Å3, and Z = 4. The crystal structure of dinilawiite (R1 = 0.0363 for 3190 I > 2σI), contains [Pb4OAl(OH)6]3+ chains formed by linkages of alternating OPb4 tetrahedra and Al(OH)6 octahedra. The chains are linked into an open framework by bonds to thiosulfate groups. Large channels within the framework contain H2O groups and a disordered mixed thiosulfate/sulfate group.

The new mineral zincochenite, Pb4Zn(OH)6(SO4)2 (IMA2022-025), was found in the Redmond mine, Haywood County, North Carolina, USA, where it occurs in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Zincochenite was found in vugs in massive galena-sphalerite-chalcopyrite-quartz in close association with bechererite, chenite, cherokeeite, elyite, lanarkite, and steverustite. Zincochenite crystals vary in habit including tablets, blades, and prisms, up to about 0.5 mm in maximum dimension. Crystals always occur in tightly intergrown subparallel clusters. The color is most commonly light blue, the streak is white, and the luster is vitreous to resinous. The mineral is brittle with curved and irregular fracture and one fair cleavage, probably on . The Mohs hardness is about 3½. The calculated density is 5.939 g/cm3. The mineral is biaxial (−) with α = 1.875(5), β = 1.900(5), γ = 1.915(5). The 2V is 78.4(5)° with strong r > v dispersion. The partially determined optical orientation is Y ≈ and there is no pleochroism. Electron microprobe analyses provided the empirical formula Pb4.00(Zn0.94Cu2+0.06)Σ1.00(SO4)1.81(S2O3)0.19(OH)6. Zincochenite is triclinic, P, a = 5.883(4), b = 7.938(5), c = 7.948(5) Å, α = 110.511(12), β = 98.497(10), γ = 100.152(8)°, V = 333.2(3) Å3, and Z = 1. Zincochenite is isostructural with chenite. In the crystal structure (R1 = 0.0874 for 936 I > 2σI), short bonds between the Pb atoms and OH groups define a chain along [011] and these chains are bridged by ZnO2(OH)4 octahedra to form sheets parallel to . SO4 tetrahedra decorate both sides of the sheets. The sheets are linked together in the direction via long Pb–O bonds and hydrogen bonds.

The new minerals finescreekite, [Pb4(OH)4](S2O3)2 (IMA2022–030), and hayelasdiite, [Pb4O1.5(OH)2.5]2[Cu+5(S2O3)4(S2O2OH)2(H2O)]·4H2O (IMA2022–021), were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Finescreekite was found in close association with anglesite, cubothioplumbite, redmondite, and steverustite. Hayelasdiite was found in close association with anglesite and steverustite. Finescreekite properties: colorless tablets to about 1.5 mm across; white streak; resinous to adamantine luster; brittle; Mohs hardness ∼ 2½; curved, stepped fracture; excellent cleavage on {001}, fair on {100}, {010}, and {110}; 5.675 g/cm3 calculated density; biaxial (−) with α = 2.00(1), β = 2.04(calc), γ = 2.065(calc), 2V = 75.9(5)°. Hayelasdiite properties: colorless prisms and blades to about 0.5 mm in length; white streak; vitreous to subadamantine luster; brittle; Mohs hardness ∼ 2½; curved fracture; perfect cleavage on {010}; 4.909 g/cm3 calculated density; biaxial (−) with α = 1.89(1), β = 1.95(calc), γ = 1.97(calc), 2V = 58(5)°. Electron probe microanalyses provided the empirical formulae [Pb4(OH)4](S2O3)1.76(SO4)0.24 and [Pb4.00O1.5(OH)2.5]2[Cu+5.00(S2O3)3.24(SO4)0.76(S2O2OH)2(H2O)]·4H2O for finescreekite and hayelasdiite, respectively. Finescreekite is Orthorhombic, P212121, a = 8.2330(9), b = 10.7128(13), c = 14.8256(13) Å, V = 1307.6(2) Å3, and Z = 4. Hayelasdiite is triclinic, P, a = 7.52089(15), b =14.9345(3), c = 17.9895(13) Å, α = 106.727(8), β = 90.966(6), γ = 90.031(6)°, V = 1934.79(16) Å3, and Z = 2. The structures of finescreekite (R1 = 0.061 for 1440 I > 2σI) and hayelasdiite (R1 = 0.055 for 5636 I > 2σI) both contain cubane-like Pb4O4 clusters, [Pb4(OH)4]4+ in finescreekite and [Pb4O1.5(OH)2.5]2.5+ in hayelasdiite. The structure of hayelasdiite also contains a decorated double chain with the formula [Cu+5(S2O3)4(S2O2OH)2(H2O)]5−.

The new minerals boojumite, Pb8O4(OH)2(S2O3)3 (IMA2022-028), and kennygayite, [Pb4O2(OH)2](SO4) (IMA2022-032), were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Boojumite was found in close association with bechererite, caledonite, cubothioplumbite, hexathioplumbite, hydroredmondite, redmondite, steverustite, and sulfatoredmondite. Kennygayite was found in close association with bechererite, chenite, cherokeeite, redmondite, sidpietersite, and steverustite. Boojumite properties: yellow prisms or blades to about 0.3 mm long; very pale yellow streak; adamantine luster; brittle; Mohs hardness ∼ 2½; irregular fracture; no cleavage; 6.619 g/cm3 calculated density; biaxial (−) with α = 2.0350(calc.), β = 2.0710(calc.), γ = 2.0725(calc.), 2V = 23(3)°. Kennygayite properties: colorless to pale yellow wedges and lozenge-shaped wafers, up to about 1 mm across; white streak; adamantine luster; brittle; Mohs hardness ∼ 2½; irregular, stepped fracture; perfect cleavage on {001}; 7.078 g/cm3 calculated density; biaxial (−) with α = 1.98(calc.), β = 2.01 (est.), γ = 2.09 (calc.), 2V = 58(5)°. Electron probe microanalyses provided the empirical formulae Pb8O4(OH)2(S2O3)2.57(SO4)0.43 and [Pb4O2(OH)2](SO4)0.87(S2O3)0.13 for boojumite and kennygayite, respectively. Boojumite is orthorhombic, Pnma, a = 14.0103(8), b = 20.5529(10), c = 7.2668(5) Å, V = 2092.5(2) Å3, and Z = 4. Kennygayite is triclinic, P, a = 6.3785(5), b = 7.4519(6), c = 10.3112(8) Å, α = 75.234(5), β = 79.388(6), γ = 88.175(6)°, V = 465.76(6) Å3, Z = 2. The structures of boojumite (R1 = 0.057 for 1538 I > 2σI) and kennygayite (R1 = 0.046 for 2419 I > 2σI) are both based on chains of edge-sharing oxocentered OPb4 tetrahedra. The chain in boojumite is sinuous, whereas that in kennygayite is zig-zag.

The new minerals haywoodite, [Pb(H2O)10)][Zn12(OH)20(H2O)(SO4)3] (IMA2021-115), and hanahanite, [Zn8(OH)14(SO4)]·3H2O (IMA2022-012), were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Haywoodite has the following properties: colorless to pale pink pseudohexagonal tablets and barrel-like prisms up to about 0.5 mm in diameter; white streak; vitreous luster; brittle; Mohs hardness 2½; curved and stepped fracture; one perfect cleavage on {011}; 3.27(2) g/cm3 measured density; biaxial (−) with 1.588(2), β = 1.600(2), γ = 1.607(2), and 2V (meas.) = 76(2)°. Hanahanite has the following properties: light blue prisms up to 0.3 mm in length; white streak; vitreous luster; brittle; Mohs hardness 3; curved fracture; one very good cleavage on {001}; 3.28(2) g/cm3 measured density; uniaxial (−) with ω = 1.636(3) and ε = 1.620(3). Electron probe microanalyses provided the empirical formulae Pb1.36Zn11.97S3.00O43H41.33 and (Zn6.69Cu1.27Co0.01)Σ7.97S1.00O21H20.04 for haywoodite and hanahanite, respectively. Haywoodite is triclinic, P1¯, a = 8.35298(19), b = 13.2769(7), c = 18.2744(13) Å, α = 92.427(8), β = 90.419(6), γ = 108.214(4)°, V = 1922.94(18) Å3, and Z = 2. Hanahanite is hexagonal, P63, a = 8.312(2), c = 15.295(2) Å, V = 915.2(5) Å3, and Z = 2. The structures of haywoodite (R1 = 0.037 for 6876 I > 2σI) and hanahanite (R1 = 0.065 for 772 I > 2σI) both contain gordaite-like sheets. In the haywoodite structure, a disordered interlayer region contains approximately one Pb and ten H2O pfu. In the hanahanite structure, ZnO4 tetrahedra in adjacent sheets are linked by sharing corners and the interlayer region only contains an H2O group.

The new minerals cherokeeite, [Pb 2 Zn(OH) 4 ](SO 4)ÁH 2 O (IMA2022-016), and cuprocherokeeite, [Pb 8 Zn 3 Cu 2þ (OH) 16 ](SO 4) 4 Á4H 2 O (IMA2022-086), were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur together in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Cherokeeite has the following properties: colorless to pale pink prisms or blades to about 1 mm; white streak; vitreous luster; brittle; Mohs hardness 2½; splintery fracture; at least two perfect cleavages; 5.011 g/cm 3 calculated density; biaxial (þ) with a ¼ 1.745(5), b ¼ 1.770(5), c ¼ 1.805(5), and 2V ¼ 85(2)8. Cuprocherokeeite has the following properties: light blue prisms or blades to about 1 mm; very pale bluish-white streak; vitreous luster; brittle; Mohs hardness 2½; irregular, curved fracture; probably two good cleavages; 5.032 g/cm 3 calculated density; biaxial (þ) with a ¼ 1.760(5), b ¼ 1.770(5), c ¼ 1.800(5), and 2V (meas.) ¼ 65(3)8. Electron probe microanalyses provided the empirical formulae [Pb 2.00 Zn 1.00 (OH) 4 ](SO 4) 0.85 (S 2 O 3) 0.15 ÁH 2 O and [Pb 8.14 (Zn 2.52 Cu 2þ 1.34)(OH) 16 ][(SO 4) 3.07 (S 2 O 3) 0.93 ]Á4H 2 O for cherokeeite and cuprocherokeeite, respectively. Cherokeeite is monoclinic, P2 1 /n, a ¼ 17.1697(7), b ¼ 6.47173(19), c ¼ 17.5304(12)Å, b ¼ 115.440(8)8, V ¼ 1759.06(19)Å 3 , and Z ¼ 8. Cuprocherokeeite is monoclinic, P2 1 /n, a ¼ 12.6828(5), b ¼ 9.4629(5), c ¼ 14.7876(8)Å, b ¼ 94.798(4)8, V ¼ 1768.53(15)Å 3 , and Z ¼ 2. The structures of cherokeeite (R 1 ¼ 0.0425 for 2681 I. 2rI) and cuprocherokeeite (R 1 ¼ 0.0741 for 2411 I. 2rI) both contain edge-sharing chains of octahedra decorated by Pb 2þ cations, which are strongly bonded to the chains via short Pb-O bonds. In cherokeeite, the octahedral cations are all Zn, whereas in cuprocherokeeite, one in every four cations is Cu 2þ .

The new minerals cubothioplumbite (IMA2021-091) and hexathioplumbite (IMA2021-092), both with the ideal formula [Pb 4 (OH) 4 ]Pb(S 2 O 3) 3 , were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur together in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. Cubothioplumbite has the following properties: yellow equant crystals to about 0.5 mm; white streak; adamantine luster; brittle; Mohs hardness 3; conchoidal fracture; no cleavage; 5.748 g/cm 3 calculated density; isotropic with n. 2.00. Hexathioplumbite has the following properties: colorless hexagonal prisms to about 1 mm; white streak; adamantine luster; brittle; Mohs hardness 2½; curved fracture; no cleavage; 5.531 g/cm 3 calculated density; uniaxial (À) with x ¼ 2.005(5) and e ¼ 1.995(5). Electron probe microanalyses provided the empirical formulae [Pb 4 (OH) 4 ]Pb(S 2 O 3) 2.72 (SO 4) 0.28 and [Pb 4 (OH) 4 ]Pb(S 2 O 3) 2.68 (SO 4) 0.32 for cubothioplumbite and hexathioplumbite, respectively. Cubothioplumbite is cubic, Pa 3, a ¼ 14.9179(13)Å, V ¼ 3319.9(9) A 3 , and Z ¼ 8. Hexathioplumbite is hexagonal, P6 3 , a ¼ 10.7213(10), c ¼ 8.6541(6)Å, V ¼ 861.49(17)Å 3 , and Z ¼ 2. The structures of cubothioplumbite (R 1 ¼ 0.0354 for 1090 I. 2rI) and hexathioplumbite (R 1 ¼ 0.0791 for 1062 I. 2rI) both contain cubane-like [Pb 4 (OH) 4 ] 4þ structural units.

The new minerals redmondite (IMA2021–072), [Pb8O2Zn(OH)6](S2O3)4, hydroredmondite (IMA2021–073), [Pb8O2Zn(OH)6](S2O3)4·2H2O, and sulfatoredmondite (IMA2021–089), [Pb8O2Zn(OH)6](SO4)4·6H2O, were found in the Redmond mine, Haywood County, North Carolina, USA, where they occur together in a highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates. The properties of redmondite are as follows: colorless to shades of brown, transparent equant rhombs to about 1 mm; white streak; adamantine luster; brittle; Mohs hardness 2; conchoidal fracture; no cleavage; 5.757 g/cm3 calculated density; biaxial with α = 1.96–1.97, β = 1.97–1.98, γ = 1.97–1.98; extreme dispersion. The properties of hydroredmondite are as follows: colorless, transparent prisms, blades, and tablets up to about 1 mm; white streak; adamantine luster; brittle; Mohs hardness 2; curved and stepped fracture; good cleavages on {101} and forumla⁠; 5.124 g/cm3 calculated density; biaxial (+) with α = 1.830(5), β = 1.880(calc), γ = 1.950(calc), 2Vmeas = 83(1)°. The properties of sulfatoredmondite are as follows: colorless, transparent wedge-shaped crystals to about 2 mm; white streak; adamantine luster; brittle; Mohs hardness 2; curved, irregular fracture; no cleavage; 5.173 g/cm3 calculated density; biaxial (+), α = 1.780(5), β = 1.850(calc), γ = 1.860(calc), 2Vmeas = 40(3)°; moderate r > v dispersion. Electron probe microanalyses provided the empirical formulae: Pb8.16Zn1.00S6+3.97S2−3.97O20H5.79, Pb8.00Zn1.00S6+4.00S2−4.00O22H9.98, and Pb8.00Zn0.99S6+4.00S2−0.89O29.11H17.98 for redmondite, hydroredmondite, and sulfatoredmondite, respectively. Redmondite is monoclinic, P21/c, a = 9.1672(4), b = 10.6576(4), c = 14.0620(10) Å, β = 101.173(7)°, V = 1347.83(12) Å3, and Z = 2. Hydroredmondite is monoclinic, P21/n, a = 12.5991(9), b = 9.2819(4), c = 12.9774(9) Å, β = 90.443(6)°, V = 1517.57(16) Å3, and Z = 2. Sulfatoredmondite is monoclinic, C2/m, a = 17.294(2), b = 7.3668(9), c = 12.7271(18) Å, β = 110.622(9)°, V = 1517.5(4) Å3, and Z = 2. The crystal structures of redmondite (R1 = 0.0346 for 2061 I > 2σI), hydroredmondite (R1 = 0.0346 for 3022 I > 2σI), and sulfatoredmondite (R1 = 0.0344 for 1661 I > 2σI) are all based on the same [Pb8O2Zn(OH)6]8+ structural unit.