Anthony R. Kampf, Xiangping Gu, Hexiong Yang, Chi Ma, Joe Marty
{"title":"Ebnerite and epiebnerite: NH4ZnPO4 dimorphs with zeolite-type frameworks from the Rowley mine, Arizona, USA","authors":"Anthony R. Kampf, Xiangping Gu, Hexiong Yang, Chi Ma, Joe Marty","doi":"10.1180/mgm.2024.15","DOIUrl":null,"url":null,"abstract":"<p>Ebnerite and epiebnerite, both with the ideal formula NH<span>4</span>ZnPO<span>4</span>, are new mineral species from the Rowley mine, Maricopa County, Arizona, USA. They occur in an unusual bat-guano-related, post-mining assemblage of phases. Epiebnerite grows epitactically on ebnerite and replaces it. Ebnerite and epiebnerite are found in intimate association with alunite, halite, mimetite, newberyite, sampleite, struvite and wulfenite on hematite-rich quartz–baryte matrix. Crystals of ebnerite are colourless narrow prisms up to ~0.3 mm in length. The streak is white, lustre is vitreous, Mohs hardness is ~2, tenacity is brittle and fracture is splintery. The density is 2.78(2) g⋅cm<span>–3</span>. Ebnerite is optically uniaxial (–) with ω = 1.585(2) and ɛ = 1.575(2). Epiebnerite occurs as colourless prisms or blades, up to about 10 × 3 × 2 μm, in parallel growth forming ribs with serrated edges epitactic on ebnerite prisms. The streak is white, lustre is vitreous, Mohs hardness is probably ~2, tenacity is brittle. The calculated density is 2.851 g⋅cm<span>–3</span>. Epiebnerite is optically biaxial with all indices of refraction near 1.580. Electron microprobe analysis gave the empirical formula [(NH<span>4</span>)<span>0.89</span>K<span>0.06</span>]<span>Σ0.95</span>(Zn<span>0.96</span>Cu<span>0.07</span>)<span>Σ1.03</span>[(P<span>0.97</span>Si<span>0.03</span>)<span>Σ1.00</span>O<span>4</span>] for ebnerite and [(NH<span>4</span>)<span>0.67</span>K<span>0.28</span>]<span>Σ0.95</span>(Zn<span>0.99</span>Cu<span>0.02</span>)<span>Σ1.02</span>(P<span>1.00</span>O<span>4</span>) for epiebnerite. Ebnerite is hexagonal, <span>P</span>6<span>3</span>, with <span>a</span> = 10.67051(16), <span>c</span> = 8.7140(2) Å, <span>V</span> = 859.25(3) Å<span>3</span> and <span>Z</span> = 8. Epiebnerite is monoclinic, <span>P</span>2<span>1</span>, with <span>a</span> = 8.796(16), <span>b</span> = 5.457(16), <span>c</span> = 8.960(16) Å, β = 90.34(6)°, <span>V</span> = 430.1(17) Å<span>3</span> and <span>Z</span> = 4. The structures of ebnerite (<span>R</span><span>1</span> = 0.0372 for 1168 <span>I</span><span>o</span> > 2σ<span>I</span> reflections) and epiebnerite (known from synthetic monoclinic NH<span>4</span>ZnPO<span>4</span>) are zeolite-like frameworks based upon corner-sharing linkages between alternating ZnO<span>4</span> and PO<span>4</span> tetrahedra with channels in the frameworks hosting the NH<span>4</span> groups. The two structures are topologically distinct. Ebnerite belongs to the family of ‘stuffed derivatives’ of tridymite, whereas epiebnerite possesses an ABW-type zeolite structure.</p>","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mineralogical Magazine","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1180/mgm.2024.15","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MINERALOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Ebnerite and epiebnerite, both with the ideal formula NH4ZnPO4, are new mineral species from the Rowley mine, Maricopa County, Arizona, USA. They occur in an unusual bat-guano-related, post-mining assemblage of phases. Epiebnerite grows epitactically on ebnerite and replaces it. Ebnerite and epiebnerite are found in intimate association with alunite, halite, mimetite, newberyite, sampleite, struvite and wulfenite on hematite-rich quartz–baryte matrix. Crystals of ebnerite are colourless narrow prisms up to ~0.3 mm in length. The streak is white, lustre is vitreous, Mohs hardness is ~2, tenacity is brittle and fracture is splintery. The density is 2.78(2) g⋅cm–3. Ebnerite is optically uniaxial (–) with ω = 1.585(2) and ɛ = 1.575(2). Epiebnerite occurs as colourless prisms or blades, up to about 10 × 3 × 2 μm, in parallel growth forming ribs with serrated edges epitactic on ebnerite prisms. The streak is white, lustre is vitreous, Mohs hardness is probably ~2, tenacity is brittle. The calculated density is 2.851 g⋅cm–3. Epiebnerite is optically biaxial with all indices of refraction near 1.580. Electron microprobe analysis gave the empirical formula [(NH4)0.89K0.06]Σ0.95(Zn0.96Cu0.07)Σ1.03[(P0.97Si0.03)Σ1.00O4] for ebnerite and [(NH4)0.67K0.28]Σ0.95(Zn0.99Cu0.02)Σ1.02(P1.00O4) for epiebnerite. Ebnerite is hexagonal, P63, with a = 10.67051(16), c = 8.7140(2) Å, V = 859.25(3) Å3 and Z = 8. Epiebnerite is monoclinic, P21, with a = 8.796(16), b = 5.457(16), c = 8.960(16) Å, β = 90.34(6)°, V = 430.1(17) Å3 and Z = 4. The structures of ebnerite (R1 = 0.0372 for 1168 Io > 2σI reflections) and epiebnerite (known from synthetic monoclinic NH4ZnPO4) are zeolite-like frameworks based upon corner-sharing linkages between alternating ZnO4 and PO4 tetrahedra with channels in the frameworks hosting the NH4 groups. The two structures are topologically distinct. Ebnerite belongs to the family of ‘stuffed derivatives’ of tridymite, whereas epiebnerite possesses an ABW-type zeolite structure.
期刊介绍：
Mineralogical Magazine is an international journal of mineral sciences which covers the fields of mineralogy, crystallography, geochemistry, petrology, environmental geology and economic geology. The journal has been published continuously since the founding of the Mineralogical Society of Great Britain and Ireland in 1876 and is a leading journal in its field.
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