Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
搜索矿物的性质搜索矿物的化学Advanced Locality Search随意显示任何一 种矿物Random Locality使用minID搜索邻近产地Search Articles搜索词汇表更多搜索选项
╳Discussions
💬 Home🔎 Search📅 LatestGroups
EducationOpen discussion area.Fakes & FraudsOpen discussion area.Field CollectingOpen discussion area.FossilsOpen discussion area.Gems and GemologyOpen discussion area.GeneralOpen discussion area.How to ContributeOpen discussion area.Identity HelpOpen discussion area.Improving Mindat.orgOpen discussion area.LocalitiesOpen discussion area.Lost and Stolen SpecimensOpen discussion area.MarketplaceOpen discussion area.MeteoritesOpen discussion area.Mindat ProductsOpen discussion area.Mineral ExchangesOpen discussion area.Mineral PhotographyOpen discussion area.Mineral ShowsOpen discussion area.Mineralogical ClassificationOpen discussion area.Mineralogy CourseOpen discussion area.MineralsOpen discussion area.Minerals and MuseumsOpen discussion area.PhotosOpen discussion area.Techniques for CollectorsOpen discussion area.The Rock H. Currier Digital LibraryOpen discussion area.UV MineralsOpen discussion area.Recent Images in Discussions
Mineralogical ClassificationIMA 2015-071 = castellaroite
10th Sep 2016 11:29 UTCMarco E. Ciriotti Manager
▪ Kampf, A.R., Cámara, F., Ciriotti, M.E., Nash, B.P., Balestra, C., Chiappino, L. (2016): Castellaroite, Mn2+3(AsO4)2⋅4.5H2O, a new mineral from Italy related to metaswitzerite. European Journal of Mineralogy, 28, 687-696.
Abstract:
Castellaroite (IMA2015-071), Mn2+3(AsO4)2 · 4.5H2O, is a new secondary arsenate mineral from the Monte Nero mine, Rocchetta Vara, La Spezia, Liguria, Italy and the Valletta mine, near Canosio, Cuneo, Piedmont, Italy. It crystallized from As- and Mn-rich hydrothermal fluids in an oxidizing environment. At Monte Nero, it is associated with coralloite, manganohörnesite, rhodochrosite, sarkinite, sterlinghillite, strashimirite and wallkilldellite. At Valletta, it is associated with braccoite, hematite, manganberzeliite, orthoclase and tiragalloite. Castellaroite occurs as thin blades, flattened on [001], striated and elongated parallel to [100] and exhibiting the forms {110}, {012} and {001}. The mineral is colourless and transparent with a vitreous to silky lustre and white streak. Crystals are flexible with a curved fracture, and one perfect cleavage on {001}. The Mohs’ hardness is 2½. The measured and calculated densities are 3.14(2) g · cm-3 and 3.164 g · cm-3, respectively. The mineral is easily soluble in dilute HCl at room temperature. Optically, castellaroite crystals are biaxial (–), with α = 1.644(1), β = 1.662(1) and γ = 1.667(1) (white light); 2V = 57(1)°; dispersion r < v, moderate; the optical orientation Y = b; Z ≈ a. The Raman spectrum is dominated by features corresponding to the AsO4 group and also confirms the presence of H2O. Electron-microprobe analyses gave the empirical formula Mn2+3.02(As1.94P0.06)Σ2.00O12.5H8.96, based on 12.5 O apfu. Castellaroite is monoclinic, P21/n, with the unit-cell parameters: a = 8.7565(8), b = 13.4683(13), c = 18.652(2) Å, β = 94.876(7)°, V = 2191.7(4) Å3 and Z = 8. The eight strongest lines in the X-ray powder diffraction pattern are [dobs/Å (I) (hkl)]: 10.90(100)(011), 9.27(67)(002), 6.97(42)(–111), 3.323(47)(multiple), 3.043(87) (-134,204,–232), 2.656(85)(multiple), 2.165(46)(multiple), and 1.5589(32)(multiple). The crystal structure was refined to R1 = 0.118 for 2513 observed reflections [Fo > 4σF]. The structure contains kinked chains of edge-sharing MnO6 octahedra parallel to [100]. The chains are linked to each other by corner-sharing, forming sheets parallel to {001} and AsO4 tetrahedra corner-link with octahedra in the sheet, forming a heteropolyhedral layer. Edge-sharing MnO6–MnO5 dimers share corners with octahedra and tetrahedra in adjacent layers, thereby linking them in the [001] direction. The heteropolyhedral layer is topologically identical to those in the structures of the phosphate minerals: angarfite, bakhchisaraitsevite, mejillonesite, metaswitzerite, rimkorolgite and switzerite. Overall, the structure is most similar to that of metaswitzerite.
15th Sep 2016 18:59 UTCKnut Edvard Larsen 🌟 Manager
版权所有© mindat.org1993年至2024年,除了规定的地方。 Mindat.org全赖于全球数千个以上成员和支持者们的参与。
隐私政策 - 条款和条款细则 - 联络我们 - Report a bug/vulnerability Current server date and time: 2024.5.8 03:11:23
隐私政策 - 条款和条款细则 - 联络我们 - Report a bug/vulnerability Current server date and time: 2024.5.8 03:11:23