Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography
╳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 2016-066 = murakamiite
25th Feb 2018 13:51 UTCMarco E. Ciriotti Manager
▪ Imaoka, T., Nagashima, M., Kano, T., Kimura, J.-I., Chang, Q., Fukuda, C. (2017): Murakamiite, LiCa2Si3O8(OH), a Li-analogue of pectolite, from the Iwagi Islet, southwest Japan. European Journal of Mineralogy, 29, 1045-1053.
Abstract:
Murakamiite (IMA2016-066), ideally LiCa2Si3O8(OH), is a new mineral that was recently discovered in an aegirine-augite albitite exposed on the Iwagi Islet, Ehime Prefecture, Japan. It occurs as prismatic crystals and monomineralic aggregates up to 1.7 mm long, is white to colourless with a white streak, and has a vitreous to silky lustre. It has a Mohs hardness of 4½–5 and is brittle with a splintery fracture and perfect {100} and {001} cleavage. Measured and calculated densities are Dmeas = 2.86(1) and Dcalc = 2.85(1) g·cm−3, respectively. Murakamiite is optically biaxial (+) and non-pleochroic, with refractive indices (in white light) of α = 1.602(1), β = 1.611(1), γ = 1.643(1), and with 2Vmeas = 56–59(2)° and 2Vcalc = 57°. Dispersion is weak, with r > v. The optical orientation is X^c 10–11°, Y^a 10–14°, Z^b 0–5°. Murakamiite is triclinic, belonging to space group P-1 with the unit-cell parameters a = 7.9098(2) Å, b = 7.0320(2) Å, c = 6.9863(2) Å, α = 90.596(2)°, β = 95.589(2)°, γ = 102.767(2)°, V = 376.98(2) Å3 (Z = 2). The eight strongest lines in the X-ray powder diffraction pattern are [dobs/Å(I)(h k l)]: 2.897(100)(2Embedded Image 0), 3.055(49)(012, 102, 1Embedded Image Embedded Image ), 3.295(41) (10Embedded Image ), 3.225(33)(201), 3.845(20)(200), 2.284(19)(10Embedded Image ), 2.720(15)(12Embedded Image , 2Embedded Image 1, 20Embedded Image ), and 6.962(15)(001). The chemical composition is (average of sixteen analyses by LA–ICP–MS, H2O by TG–DTA, wt%): SiO2 54.94, Al2O3 0.01, FeO 0.38, MnO 0.80, MgO 0.04, CaO 34.14, Na2O 4.37, Li2O 2.52 and H2O 2.80. The empirical formula of murakamiite, based on 9 O apfu, is (Li0.55Na0.46)Σ1.01(Ca1.98Mn0.04Fe0.02)Σ2.04Si2.98O8(OH)1.01; thus, muakamiite is a H-bearing pyroxenoid with three-periodicity of SiO4 tetrahedra and the Li-analogue of pectolite. The species is named in honour of the late Professor Emeritus Nobuhide Murakami (1923–1994) of Yamaguchi University, Japan. Type specimens are housed in the National Museum of Nature and Science, Tsukuba, Japan, and the Geological and Mineralogical Museum of Faculty of Science, Yamaguchi University, Japan.
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 17, 2024 20:40:57
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 17, 2024 20:40:57