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 ClassificationRruffite (IMA 2009-077) type-description
29th Jul 2011 09:14 UTCMarco E. Ciriotti Manager
▪ Yang, H., Jenkins, R.A., Downs, R.T., Evans, S.H., Tait, K.T. (2011): Rruffite, Ca2Cu(AsO4)2·2H2O,a new member of the roselite group, from Tierra Amarilla, Chile. Canadian Mineralogist, 49, 877-884.
Abstract:
A new mineral species, rruffite, ideally Ca2Cu(AsO4)2·2H2O, has been found in the oxidation zone of the Cu–As orebody in the Maria Catalina mine, Tierra Amarilla, Chile. It is a secondary mineral and occurs in granular or blocky aggregates and druses. Associated minerals include quartz, barite, mansfieldite, alumopharmacosiderite, conichalcite, metazeunerite, and barahonite-(Al). Rruffite is pale or light blue, transparent with white streak and vitreous luster. It is brittle, has a Mohs hardness of ~3 and a perfect cleavage on {010}, and is twinned on (100). The measured and calculated densities are 3.79(3) and 3.77(2) g/cm3, respectively. Rruffite is insoluble in water, acetone, and hydrochloric acid. Optically, it is biaxial (–), with alpha 1.725(1), β 1.734(1), gamma 1.740(1), 2Vmeas 80(2)°, Y = b, X c 49°, and it does not fluoresce under long- or short-wave ultraviolet light. The dispersion is weak, with r < v. An electron-microprobe analysis yielded the empirical formula Ca2.01Cu1.01(AsO4)2.02·1.9H2O. Rruffite, isostructural with roselite, is monoclinic, with space group P21/c and unit-cell parameters a 5.8618 (2), b 12.7854 (5), c 5.7025 (2) Å, β 109.425(2)°, and V 403.05(3) Å3. Its structure is characterized by isolated CuO4(H2O)2 octahedra that are linked by corner-sharing with AsO4 tetrahedra to form the kröhnkite-type chains parallel to the c axis. These chains are linked together by large Ca cations and hydrogen bonding. Owing to the strong Jahn–Teller effect, the MO4(H2O)2 octahedron in rruffite is the most distorted of all known roselite-group minerals (M = Cu, Co, Mn, Mg, and Zn) in terms of the quadratic elongation of the octahedra. The Raman spectra of rruffite resemble those of arsenate minerals of the roselite group.
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 25, 2024 22:02:38
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 25, 2024 22:02:38