IMPORTANT MESSAGE. We need your support now to keep running. Click here to find out why.
Log InRegister
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 Educators
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

IMA 2013-102 = fluorlamprophyllite

Posted by Marco E. Ciriotti  
Marco E. Ciriotti April 18, 2018 09:29AM
▪ Andrade, M.B., Yang, H., Downs, R.T., Farber, G., Contreira Filho, R.R., Evans, S.H., Loehn, C.W., Schumer, B.M. (2018): Fluorlamprophyllite, Na3(SrNa)Ti3(Si2O7)2O2F2, a new mineral from Poços de Caldas alkaline massif, Morro do Serrote, Minas Gerais, Brazil. Mineralogical Magazine, 82, 121-131.

A new mineral species, fluorlamprophyllite (IMA 2013-102), ideally Na3(SrNa)Ti3(Si2O7)2O2F2, has been found in the Poços de Caldas alkaline massif, Morro do Serrote, Minas Gerais, Brazil. Alternatively, the idealized chemical formula could be written as (SrNa)[(Na3Ti)F2][Ti2(Si2O7)2O2], setting the large interlayer cations before the cations of the layer. Fluorlamprophyllite is the F-analogue of lamprophyllite. It is associated with aegirine, analcime, natrolite, nepheline and microcline. Fluorlamprophyllite crystals are brownish-orange and bladed. The mineral is transparent with a pale yellow streak and an adamantine luster. It is brittle and has a Mohs hardness of ~3; cleavage is perfect on {100} and no parting was observed. The calculated density is 3.484 g/cm3. Optically, fluorlamprophyllite is biaxial (+), with α = 1.735(7), β = 1.749(7), and γ = 1.775(9), 2Vmeas = 72(3)°. An electron microprobe analysis produced an average composition (wt%) (9 points) of Na2O 10.63(30), K2O 0.47(3), SiO2 30.51(13), SrO 18.30(24), MgO 0.81(17), Al2O3 0.23(2), CaO 1.11(7), MnO 5.03(38), TiO2 27.41(87), Fe2O3 2.45(37), F 2.86(23), plus H2O 1.00 (added to bring the total close to 100 %), -O=F -1.20, with the total = 98.61%. The elements Nb and Ba were sought, but contents were below microprobe detection limits. The resultant chemical formula was calculated on the basis of 18 (O + F) atoms per formula unit. The addition of 1.00 wt% H2O brought [F+(OH)] = 2 pfu, yielding (Na2.63 Sr1.35Mn0.54 Ca0.15Mg0.15 K0.08)Σ=4.90 (Ti2.63Fe0.24Al0.04)Σ=2.91Si3.89O16[F1.15(OH)0.85]Σ=2.00. It is monoclinic, with space group C2/m and unit-cell parameters a = 19.255(2), b = 7.0715(7), c = 5.3807(6) Å, β = 96.794(2)°, and V = 727.5(1) Å3. Its structure is a layered silicate inasmuch as the O atoms are arranged in well-defined, though not necessarily close-packed layers.
Ronnie Van Dommelen August 10, 2018 12:33PM
Page already updated
Sorry, only registered users may post in this forum.

Click here to login

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2018, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: October 19, 2018 19:11:55
Go to top of page