DOCSLIB.ORG

THE OPTICAL PROPERTIES of the HUMITE GROUP Espbn S. Lensbn

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
THE OPTICAL PROPERTIES of the HUMITE GROUP Espbn S. Lensbn 354 TEE AMERICAN MINERALOGIST THE OPTICAL PROPERTIES OF THE HUMITE GROUP EspBn S. LensBN A considerable number of specimensof the humite group were examined optically in an attempt to find some consistent differ- ences that would enable one to quickly and with assurance,dis- tinguish between the members of the group. Assuming that the specimens were correctly labelled, the resulting data and in par- ticular the indices of refraction for each member of the group showed a surprisingly wide variation and within about the same range for each of the species,so that no satisfactory data for deter- minative purposeswas had and the suspicion was raised that many of the specimensmight be incorrectly labelled. It was accordingly decided that any reliable data on the group must be based on the examination of material that had been analyzed or otherwise positively identified. I was fortunate enough to secure the material studied by Pen- field and Howel from Professor Ford of Yale University, and that studied by Sjcigren2from Professor Aminoff of Stockholm. I ex- press my sincere thanks to Professors Ford and Aminoff for the use of these materials. The study was made by the immersion method, and the indices of refraction were determined in sodium light and should be in error * 0.001. Some of the plates of Sj<igrenshowed zonal growths. All of the specimensexamined, except the one from Franklin, associatedwith norbergite, are optically f , and all have large to very large axial angles. The pleochroism is stronger for the darker colored specimenand in all the pleochroic formula is: X: yellowish brownl y:paler yellowishbrown; Z : colorless. Taer,u I gives the indices of refraction for five analyzed speci- mens of chondrodite from as many localities, for a specimen that was similar to the analyzed sample from a sixth locality and for the mineral from four other localities. The indices of refraction for all of the five analyzed specimensare very much alike, those I Penfield, S. L. and Howe, T. H. On the Chemical Composition of Chondro- dite, Humite, and Clinohumite. Am. J. 5c.,47,188-200, 1894. 2 Sjdgren, IIj. Chondrodite von Kafveltorp, Zei.t. Kryst. Min.,7, ll3-152,1882, Beil,ritge zur Minerdogie Schweilens, Bul,l. Geol. Inst. IJpsuI,a, I, t-54, 1892; 2,39-54, 1894. JOURNAL MINERALOGICAL SOCIETV OF AMEruCA 355 xb#o F-o\<1 oro 40 x= &sp $. 4 P =r €NO\oro NN jS ;i R da q {r eeq r;cos -;<.;-;^i NN 'o€ dii ,O V) t :.F E eo9 E$fr ! b€E v\O€ 9 E;A ild O C)r .r4tr8 q{ q bN SUUFF p.lob Hqq 4q RK :t'O@ OH On N NN d d JJJ Rin 4A- !dB O O\\OO\c)\Oo\O\Oc)@ 4.tNhn:\ordord 6N o ii.g Z:*E S ;dGJdo<,od-.; NN o-; ut^ iNh qqq :; Hdd \o." !; derrDoO ON i 9NS :N FA\ON46 $<r O 9\O\O o o- N9 d;-;J+.i O Hdd \N r:-.t\o<roooDbco <roo \o@ ONNN4OiON NN N\O q\ qE DN NOSOSc)TO\C N c;6i N o i €N 3 EE'-., F .to!- qqq A ;:"H N oa N f 599 \o \o \o 6 JJ.-i N SONc)N 44999 E RKq€q o<{\o\oi sa rdd 3'i e s q rl .' d : ts\o\ohN drD o.n o .: tr;o oo<t\oi@ 9\o € l.i o .< F E P9 *;G*;;n - g;6;( 5.'i -; *; JJ..; if oo<tso\o €r *n odo SrEx@N\O6e+ \9 :li d;dJN.i .i-;J o hzdi( OO r -o . ^q E*;'$ <rr o\ qqq "ia EZ Xe F-o,P E 6o !9 .r td - o\oN E H'iio h\o\o I E18 .i-;J > 3Fq' ttr r-; ;o ! gf,9ssE?$"sB$*.ii ,.i . >-x o6 daa- NFt 356 TE E AM ERICAN M I N ERALOGIST for the Franklin mineral are considerably lower, while those for the Weston, Nordmark, Custer County, and Tilly Foster minerals are much higher. Analyses are available for the mineral from Nord- mark and Tilly Foster but the exact materials that furnished the analyses were not available for optical study. Tesrr II. ANlr,vses nNn Oprrcer,PRoPERTTEs or Huurte Monte Vesuvius Nordmark Nordmark Somma Yale Sjiigren Sj6gren 4102 Brownish Yellowish Light dark yellow Sray SiOz 36.63 36.74 35.M 35.2r Tio: 0.07 0.07 Mgo 56.45 56.31 47.22 48.33 CaO o.t7 0.11 FeO 2.35 2.22 10.96 7.93 MnO 1.47 1.69 ALOa 0.19 0.07 FerOa 0.68 1.06 F 3.68 3.96 3.79 4.59 KrO 0.17 0.20 NazO o.29 0.34 HrO* 2.45 t.28 f Hro- 11.8s 100.96 101.36 101.73 101.4s OforF 1.26 1.66 1.60 r.93 99.70 99.70 100.13 99.52 Sp. Gr. 3.194 3.183 3.32 3.24 3.201 3.225 d, l.62ls 1.625 1.632t0 1.627 1.635 r.643 t.649 1.656 2V 70" RnrrnrNcrs ron Teslos I lNo II s Barth, Tom. On Contact Minerals from the Pre-Cambrian in Southern Norway, Norsk, Geol.Tid.,Vnl,94-96, 1924. 'von Eckermann, Harry. The Rocks and Contact Minerals of the Mansjti Mountain, Geol. F or., Stockholm, 27 9-383, 1922. 5 Eskola, Penti. The Contact PhenomenaBetween Gneissand Limestone in Western Massachusetts,Jour. Geol., XXX, 270, 1922. TOURNAL MINERALOGICAL SOCIETY OF AMEMCA JJ/ 6 Optical data on brown crystals similar to thoseanalyzed but not on identical material. 7 Shannon,E, V. The Minerals of Idaho. U. S. Nar. Mus., Bull. 131,33F334, 1926. t Specimensfrom Tilly Fostergave: . d 1.627 1.632 1.635 1.643 p 1.638 r.640 1.645 1.655 'y 1.657 1.661 1.663 1.670 The last figuresare by GillsonnJ, L., Atn. Mineral.,ll, 284, 1926, e Optical data not closelytied to the analysesbut on specimen4806 of the Brush Collection which is very pale brown and answersthe description of the analyzed specimen. r0 No.'62 Plate 2 of Sjdgren-Optical data not closelytied to analysis. Tegr.p III. Ane,rvsrs eno Oprrcll Pnopnnrrns ol Clnqosulrrrn. Vesuvius Vesuvius Nordmark Chafiev'su Piedmontra YaIe Brush Sjdgren Lake, Ontario 4t43 2046 No.63 si02 37.78 38.03 35.86 37.42 36.83 TiOz .06 |.14 r.92 Meo 53.05 54.00 M.66 56.32 51.53 CaO trace FeO 5.64 4.83 t4.25 |.27 -4.W MnO t.t9 0.10 .28 AbOa 0.07 FerOs o.22 0.46 0.42 F 3.58 2.06 4.t6 5.04 0.03 KrO 0.15 NazO o.29 o.t2 HrO+ 1.33 1.94 1.58 o.s6 lr.u HrO- t0.12 100.38 100.86 102.42 L02.3t 99.2613 OforF 1.50 .86 r.75 2.r2 99.88 100.00 100.67 100.19 Sp.Gr. 3.219 3.184 3.35 3.17 3.258 3.222 a 1.632 1 .62514 l.652rt 1.628 1.66411 p t.6M 1 .638 1.663 t.&2 r.67s .| L.664 1 .653 1.698 2V 74" near 90o 76027', 62" Ext. 120-150 70"29', 358 TH E AM ERICA N M I NERALOGIST RelpruNcrs ron Tnsrn III. 11Optical data not closely tied to analyses. 12Walker, T. L., and Parsons, A. L.-Clinohumite {rom Chafiey's Lake, Ontario. Conh. Can. Mi.n., p. 17-18, 1927. 13Zambonini, F., -Sur la veritable nature du Titanolivine de la valler d'Ala (Piedmont), Bull. Soc.Fr. Minr., XLII, 1-30, 1919. Contains PbO.0.14,'BaO 1.30, CrrOB0.03, NiO 0.07, Optical data by Larsen. la Not uniform-Indices vary*0.005 or more. Data are for about averages. fn Tasrc II optical data are given for three analyzed specimens of humite from two localities. In Tesln III optical data are given for five analyzed specimens of clinohumite from four localities. The corresponding data for two specimens of analyzed norbergite are given in the preceding paper. Assembling the data for the four members of the humite group, Tnnr,B IV shows that on the whole, as the MgzSiOr increasesin amount the indices of refraction increase,but there is much over- lapping. The norbergite occupies a low range and can be dis- tinguished from the others by its indices of refraction. Most of the analyzed chondroditeshave p between 1.616,and 1.622, and are higher than any of the norbergites and lower than any of the humites but some of the chondrodites have B as high as any clino- humite except that from Piedmont. The humites mostly have B lower than does clinohumite but there is overlapping. Teer,n IV. Opucer, Darn ron rnr Huurro Gnoup Norbergite Chrondrodite Humite Clinohumite Compo-Mg(OH, F):. Mg(OH, F): Mg(OH, F), Mg(OH, F)z' sition MgrSiOo 2MgrSion 3Mgrsioo 4Mg2SiOr q 1.561-1 .563 t.60t-t.643 t.62r-1.632 r.623-1.664 a 1 .566-1. 570 1.616-1 .655 r.627-1.643 t.636-1.673 7 1. 587-t .590 t.636-1.670 r.649- 1.651-1 .698 Ext. Orth. 22'-29" Orth. 7"-15" 2V 45'-50' 73"-90" 700- 620-90" The variation in the indices of refraction is brought out by com- paring the data for the three minerals (chondrodite, humite, and clinohumite) from the same localities.
Load more

Recommended publications
  • The Picking Table Volume 27, No. 1 – Spring 1986
    TABLE JOURNAL of the FRANKLIN-OGDENSBURG MINERALOGICAL SOCIETY, INC. SPRING. 1986 VOLUME 27, NO.l The contents of The Picking Table are licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. F.QM.S. Notes prise a spectacular fluorescent display. For PRESIDENT'S MESSAGE years the Gerstmann Mineral Museum has displayed the collection for the delight and With the melting of the snow, the rocks of education of amateur and professional mineralo- the Buckwheat Dump emerge from their white gists alike. The Franklin Mineral Museum mantle, and the seismic tremors rumble through is most grateful to Arthur and Harriet Mitteldorf the souls of the collector community. Whatever for this most generous donation and to Ewald Spring may mean to the average mortal, to Gerstmann for its accumulation and for his FOMS members it brings a special appeal to sponsorship of the Franklin Mineral Museum dig in the dirt, not to plant, but to explore as the recipient. Transfer of the collection again the crystalline mysteries of Nature. will be effected as soon as suitable space is available to house it. Let us not lose sight of the fact that we are a community, however widespread, dedicated JLB to a great common interest and purpose: the expansion and preservation of knowledge about the world's most remarkable mineral location. ABOUT THE COVER SKETCH Like all great enterprises, this demands the efforts and participation of many. To the Located Sphalerite Occurrences—Franklin Mine extent that we share our knowledge, our time, and our interest with each other and the world, It is suggested that you refer to this hand Franklin lives.
    [Show full text]
  • Download the Scanned
    American Mineralogist, Volume 70, pages 379-387, 1985 Ma_nganesehumites and leucophoenicitesfrom Franklin and Sterling- Hill' NewJersev: 'i"? andimplications ;ifi':il1,;;lfiil11"r's' Perr J. Dullx Department of Mineral Sciences Smithsonian lnstitution, Washington, D. C. 20560 Abstract The manganesehumites, (alleghanyite, manganhumite, and sonolite),together with some Mn-bearing samplesof the Mg-humites,and the related phasesleucophoenicite and jerry- gibbsite,from the orebodiesat Franklin and SterlingHill, New Jersey,are describedtogether with analytical data. Solid solution betweenhumite and manganhumiteis at least partially continuous. Expected Mn/Mg solid solutions between alleghanyiteand chondrodite, and betweensonolite and clinohumite, are discontinuous; they are interrupted by apparently orderedphases. In all cases,the possibleorderings involve Zn as well as Mn and Mg. There are no Mn end-membersof the manganesehumites at this locality. Manganeseis apparently restricted in leucophoenicite(5.42-6.63 Mn per 7 octahedral cations) and in jerrygibbsite (7.79-8.02Mn per 9 octahedralcations). Calcium is common to both leucophoeniciteand jerrygibbsite,but among the Mn-humites,only sonoliteaccepts appreciable Ca (0.65Ca per 9 octahedralcations). There is a "threshold" level ofzinc in all studiedsamples; this "threshold" levelis a constantfor leucophoenicite1-9.3 Znper 3 Si)and alleghanyite(-O.2Zn per 2 Si). No samplesof leucophoeniciteor jerrygibbsite were found to be Zn-ftee,suggesting either that Zn is required for their stability, or that these two phasesmight not be stable as end-members.Fluorine is present in all the Mn-humites and is proportional to the Mg- content,but is absentin leucophoeniciteand jerrygibbsite. Introduction humite speciesoccur there; the Mg-humites occur in the The magnesiumhumite species(norbergite, chondrodite, host Franklin Marble for the most part, and the Mn- humite, and clinohumite) have been well-studiedand re- humites in the orebodiesthemselves.
    [Show full text]
  • Kumtyubeite Ca5(Sio4)2F2—A New Calcium Mineral of the Humite Group from Northern Caucasus, Kabardino-Balkaria, Russia
    American Mineralogist, Volume 94, pages 1361–1370, 2009 Kumtyubeite Ca5(SiO4)2F2—A new calcium mineral of the humite group from Northern Caucasus, Kabardino-Balkaria, Russia Ir I n a О. Ga l u s k I n a ,1,* BI l j a n a la z I c ,2 Th o m a s ar m B r u s T e r,2 ev G e n y v. Ga l u s k I n ,1 vI k T o r m. Ga z e e v,3 al e k s a n d e r e. za d o v,4 nI k o l a I n. Pe r T s e v,3 lIdIa je ż a k ,5 ro m a n Wr z a l I k ,6 a n d an a T o l y G. Gu r B a n o v 3 1Faculty of Earth Sciences, Department of Geochemistry, Mineralogy and Petrography, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland 2Mineralogical Crystallography, Institute of Geological Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland 3Institute of Geology of Ore Deposits, Geochemistry, Mineralogy and Petrography (IGEM) RAS, Staromonetny 35, 119017 Moscow, Russia 4OOO NPP TEPLOCHIM, Dmitrovskoye av. 71, 127238 Moscow, Russia 5Institute of Geochemistry, Mineralogy and Petrology, University of Warsaw, al. Żwirki i Wigury 93, 02-089 Warszawa, Poland 6Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland aB s T r a c T Kumtyubeite, Ca5(SiO4)2F2—the fluorine analog of reinhardbraunsite with a chondrodite-type structure—is a rock-forming mineral found in skarn carbonate-xenoliths in ignimbrites of the Upper Chegem volcanic structure, Kabardino-Balkaria, Northern Caucasus, Russia.
    [Show full text]
  • A Mineral Resembling Meerschaum from the Serpentine Range of Hampden County, Mass., with the Descriptions of Interesting Included Crystals
    Journal of the Minnesota Academy of Science Volume 4 Number 2 Article 2 1899 A Mineral Resembling Meerschaum From the Serpentine Range of Hampden County, Mass., With the Descriptions of Interesting Included Crystals. A. D. Roe Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas Part of the Earth Sciences Commons Recommended Citation Roe, A. D. (1899). A Mineral Resembling Meerschaum From the Serpentine Range of Hampden County, Mass., With the Descriptions of Interesting Included Crystals.. Journal of the Minnesota Academy of Science, Vol. 4 No.2, 268-276. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol4/iss2/2 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact [email protected]. • Mineral Resembling Meerschaum and Baffin 's Land, so that the same shore line had run through these three places. Pro fessor Arndt reported o n his investigations into orig­ inal m ethods of tcarhing science. H . Gale reported on the interesting picture of scientific activity. mingled with a broad culture, found in the delightful •· Briefe von Dr. T h co. Billroth.'' 276th Meeting, November, 1905. Secretary 's minut es lacking. Paper L , P sy chology of the Busines s Man hv•• Harlow Gale. 277th Meeting, December s, 1905. Secretary 's minutes lacking . Paper M. Glacial and l\Iorlified D rift of the ~[i ss i :;sipp i Valley from Lake Itasca to Lake Pepin, by \•\ 'arren Upham .
    [Show full text]
  • Chondrodite (Mg,Fe2+)5(Sio4)2(F,OH)
    2+ Chondrodite (Mg; Fe )5(SiO4)2(F; OH)2 c 2001 Mineral Data Publishing, version 1.2 ° Crystal Data: Monoclinic. Point Group: 2=m: Crystals rare, varied in habit, typically °attened [010], to 10 cm. Commonly as rounded grains, massive. Twinning: On 001 , common, ksimple and lamellar; possibly 015 and 305 . f g k f g f g Physical Properties: Cleavage: 100 indistinct; parting on 001 . Tenacity: Brittle. Hardness = 6{6.5 D(meas.) = 3.16{f3.26g D(calc.) = 3.177 f g Optical Properties: Transparent to translucent. Color: Light yellow, yellow, brown, red; in thin section, pale yellow or brown to colorless. Luster: Vitreous to resinous. Optical Class: Biaxial (+). Pleochroism: X = colorless, very pale yellow, brownish yellow; Y = colorless, yellow-green; Z = colorless, pale green. Orientation: Z = b; X c = 22±{31±. Dispersion: r > v; strong to weak. ® = 1.592{1.643 ¯ = 1.602{1.655 ° =^ 1.621{1.676 2V(meas.) = 71±{85± Cell Data: Space Group: P 21=c: a = 7.8404(2) b = 4.7284(3) c = 10.2539(3) ¯ = 109±20 Z = 2 X-ray Powder Pattern: Tilly Foster mine, New York, USA. (ICDD 12-527). 2.258 (100), 1.740 (70), 3.02 (45), 2.510 (45), 3.56 (35), 2.758 (35), 2.288 (35) Chemistry: (1) (2) (1) (2) SiO2 33.60 32.16 MgO 59.30 53.21 TiO2 0.06 0.20 CaO 0.00 0.00 Al2O3 0.24 0.73 F 6.61 7.11 + Fe2O3 0.05 0.60 H2O 1.46 1.20 FeO 0.86 6.08 H2O¡ 0.00 0.00 MnO 0.16 1.35 O = F 2.78 2.99 ¡ 2 Total 99.56 99.65 2+ (1) Hangelby, Finland; corresponds to (Mg5:13Fe0:04Al0:02Mn0:01)§=5:20Si1:95O8 2+ [F1:21(OH)0:56O0:23]§=2:00: (2) Kafveltorp, Sweden; corresponds to (Mg4:74Fe0:30Mn0:07 3+ Al0:05Fe0:03Ti0:01)§=5:20Si1:92O8[F1:34(OH)0:48O0:18]§=2:00: Polymorphism & Series: Forms a series with alleghanyite.
    [Show full text]
  • Spectroscopic Characterization of Manganese Minerals
    This may be the author’s version of a work that was submitted/accepted for publication in the following source: Reddy, S., Padma Suvarna, K., Reddy, G. Udayabashakar, Endo, Tamio, & Frost, Ray (2014) Spectroscopic characterization of manganese minerals. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 117, pp. 270-275. This file was downloaded from: https://eprints.qut.edu.au/62374/ c Consult author(s) regarding copyright matters This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the docu- ment is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recog- nise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to [email protected] License: Creative Commons: Attribution-Noncommercial-No Derivative Works 2.5 Notice: Please note that this document may not be the Version of Record (i.e. published version) of the work. Author manuscript versions (as Sub- mitted for peer review or as Accepted for publication after peer review) can be identified by an absence of publisher branding and/or typeset appear- ance. If there is any doubt, please refer to the published source. https://doi.org/10.1016/j.saa.2013.08.028 Spectroscopic characterization of manganese minerals S.Lakshmi Reddy1, K.Padma Suvarna2 , G.
    [Show full text]
  • Fluorine-Rich Clinohumite from Ambasamudram Marbles, Southern India: Mineralogical and Preliminary FTIR Spectroscopic Characterization
    Mineralogical Magazine, August 1998, Vol. 62(4), pp. 509-519 Fluorine-rich clinohumite from Ambasamudram marbles, Southern India: mineralogical and preliminary FTIR spectroscopic characterization M. SATISH-KUMARAND NAOYUK/NIIMI Department of Geosciences, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka-558-8585, Japan ABSTRACT Humite group minerals occur in the marbles of granulite grade at Ambasamudram, southern India. Detailed mineralogical and mineral chemical characterization indicate the mineral is a flourine-rich titanian-poor variety of clinohumite. Average MTi/Si values of 2.22 with typical XRD pattern indicate the mineral to be clinohumite. Petrological constraints on the clinohumite formation shows a high temperature (>700~ and low aco2 during its formation. The fluorine content of these clinohumites is the highest reported in any environment, with F/(F+OH) ratio reaching a value of 0.70. The high fluorine content reflect the high P-T condition of formation. The OH content of the clinohumites is around 0.59 mole fraction. Preliminary FT1R spectra of the clinohumites show eight sharp absorption peaks between wave numbers 3700 and 3400 cm -j and a broad absorption band with a peak at 3840 cm -1. The sharp peaks are due to OH in the clinohumite. The high fluorine content of the Ambasamudram clinohumites possibly resulted from the isochemical reactions involving (OH-F) silicates such as amphiboles or phlogopites. The internal fluid buffering is also supported by the stable isotope as well as the petrological studies of the marble assemblages. KEYWOROS: fluorine, clinohumite, mineralogy, FTIR, India, humite. Introduction clinohumite and titanium rich variety is commonly described as titanoclinohumite.
    [Show full text]
  • Refinement of Hydrogen Positions in Natural Chondrodite by Powder Neutron Diffraction: Implications for the Stability of Humite Minerals
    Mineralogical Maga~ine. June 2002. Vol. 66(3). pp. 44/-449 Refinement of hydrogen positions in natural chondrodite by powder neutron diffraction: implications for the stability of humite minerals A. .I. BERRyl AND M. JAMES1 1 Rcscarch School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia 1 Neutron Scattering Group, Building 58, Australian Nuclear Scicncc and Technology Organisation, PMB I, Menai NSW 2234, Australia ABSTRACT Thc structure of a natural sample of chondrodite (Mg4.xqFeoo7Si1.o40sF l54(OH)OA6) was refined using powder neutron diffraction data and the Rietveld techniquc 2; a = 4. 7204( I) A; h = o 0 (P2/h; Z = 7.8252(2) A; rx = I09.11( I); V = 1 10.2360(3) A; c = " 357.26(2) A-). Hydrogen was found to occupy the H I site. The significance of hydrogen at this site is discussed in terms of hydrogcn-bond stabilization of humite structures containing varying amounts of OH, F and Ti. Arguments are proposed as to why the F and Ti contents of natural humites usually result in only onc H pcr formula unit when there is no crystal-chemical reason why fully hydrated samples should not be favourcd. KEYWORDS:powdcr ncutron diffraction, chondrodite, Rietveld refinement, humite minerals. Introduction Humite minerals usually occur in metamor- phoscd limestones and dolomites. However, THE humitc group minerals have the general titanian clinohumite occurs in mctamorphosed formula nMg2Si04.Mgl_Ji,(F,OHh 2x02x mantle rocks (TrommsdortT and Evans, 1980) and where n = I (norbergite), 2 (chondrodite), 3 both titanian clinohumite and titanian chondrodite (humite) or 4 (clinohumite) (Jones et al., 1969).
    [Show full text]
  • Jerrygibbsite, a New Polymorph of Mne(Sioa)C(OH)Z from Franklin
    American Mineralogist, Volume 69, pages 546-552, 1984 Jerrygibbsite, a new polymorph of Mne(SiOa)c(OH)zfrom Franklin, New Jersey, with new data on leucophoenicite Prrr, J. DUNN Department of Mineral Sciences Smithsonian Institution, Washington, D.C. 20560 DoNer-o R. Peacon Department of Geological Sciences University of Michigan, Ann Arbor, Michigan 48109 Wrlrreu B. SruuoNs Department of Earth Sciences University of New Orleans, New Orleans, Louisiana 70148 aNo Enrc J. Essexe Department of Geological Sciences University of Michigan, Ann Arbor, Michigan 48109 Abstract Jerrygibbsite, ideally Mnq(SiO+)+(OH)2,is polymorphous with the Mn-humite sonolite, and a probable member of the leucophoenicitegroup. It occurs as intergrown grains with a typical metamorphic texture at Franklin, New Jersey, intimately associatedwith leuco- phoenicite. It is orthorhombic with spacegroup Pbnm or Pbn21and unit cell parametersa : 4.85(1),b : 10.70(l),and c = 28.17(3)4.The strongestlines in the powder diffraction pattern ared (I): 2.557(lN), 1.806(100),2.869(78),2.752(49),2.702(46),2.362 (39). Optical parametersinclude: biaxial negative,2V = 72", a = 1.77?(4),F = 1.7$G), y: 1.789(4);Z : a, X : b, amd Y: c. The color is violet-pink;the Mohs' hardnessis approximately5.5; the observed density is 4.00(2) and the calculated density is 4.045 g/cm3.The name is in honor of ProfessorGerald V. Gibbs of Virginia Polytechnic Institute and State University. Chemical analytical data for leucophoeniciteindicate that minor amounts of Ca andlor Zn may sel'veto stablilize leucophoenicite-groupminerals relative to humite-groupminerals at Franklin, New Jersey.
    [Show full text]
  • 1589 Vol 43#5 Art 13.Indd
    1589 The Canadian Mineralogist Vol. 43, pp. 1589-1603 (2005) CHEMICAL STATE OF SULFUR IN NATURAL AND SYNTHETIC LAZURITE BY S K-EDGE XANES AND X-RAY PHOTOELECTRON SPECTROSCOPY MICHAEL E. FLEET§, XIAOYANG LIU, SARAH L. HARMER¶ AND H. WAYNE NESBITT§ Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada ABSTRACT Lazurite with a composition close to [Na6Ca2Al6Si6O24(SO4,S)2] has been synthesized by employing CaS + CaSO4 redox in hydrothermal-pressure experiments and reduction with Re foil in piston–cylinder experiments. A royal blue lazurite formed by annealing at 1200°C and 0.5 GPa; it has an Al-rich framework (Al/Si between 1.1 and 1.2) and coexists with minor amounts of a colorless sodalite phase of S-poor, Si-excess composition. The sodalite phase of experiments without a reducing agent is haüyne. The chemical state of sulfur in the synthetic products and in lazurite from Afghanistan and Baffi n Island, Nunavut, has been investigated by S K-edge X-ray absorption near-edge structure (XANES) spectroscopy and S 2p X-ray photoelectron spectros- copy (XPS). Sulfate is the dominant species of sulfur in all samples of lazurite studied, and there are signifi cant but subordinate amounts of sulfi de bound only to Na+ cations. In addition, there is minor sulfi te in some piston–cylinder products and minor native sulfur in the minerals. Polysulfi des are not present above minimum levels of detection. Natural lazurite differs markedly from its synthetic equivalent in chemical composition and S K-edge XANES and S 2p3/2 XPS spectra, but these differences appear to have little bearing on color development.
    [Show full text]
  • NEW Daila on the STRUCTURE of Norbergffe: LOCATION OF
    1523 The Canadian M ineralo gi st Vol.35,pp. 1523-1s30(197) NEW DAilA ON THESTRUCTURE OF NORBERGffE:LOCATION OF HYDROGEN BVX.RAY DIFFRACTION FERNANDOCAMARAT CNR- Centrodi Sndiaper la Cristallpchimicae Ia Cristallografia(CSCC), via Abbiategrasso 209' I-27100 Pavta ltaly ABSTRACT T\wo crystals of OH-rich norbergite from the Alpujarride Complex @etic Cordilleras) have been analyzed, and their structue rfinedby single-crystalX-raydiftaction analysis.Tbe new dataconfirm the earlierrefinementon a comlnsition near the F end-membr, and add new insight to the crystal chemistry of this humite-groupmineral. In particular, hydrogen atoms were locatedon the difference-Fouriermap. l1eir position and the consequentstuctural constraintsto the (OH)F-1substiortion suggestthat OH-rich norbergite requirei very high pressureto crystallize, thus expLiriningthe normal occurrenceof the fluorine-dominant compositions. Keywords: norbergite,humite group, structurerefinement, electon-microprobe data,hydrogen. Sotffens Deux cristauxde norbergiterelativenent riches en oII, provenantdu complexede Alpujauide' dansles cordilldre'sbetiques d'Espague,ont 6t6 analys6s,et lur stuctre a 6td affin6epar diftaction X sur cristal unique.Les donn€esnouvelles confirment les rdsultatsde I'affinement ant6rieur,obtenu sur un cristal prochedu p0le fluo€, et ajoutentdes nouveaux renseiguements au sujet de la cristallochimiede ce membredu group de la humite. En particulier, les atomesd'hydrog0ne ont 6td repdr€ssur une projection de Fourier par diff6rence, D'aprds leur position et les contraintes structurales qui en d&oulent concernant la substitution (OII)F-', la formation de la norbergiteriche en OH requiert une pressionassez 6levde, ce qui rend comptede la pr6sencecourante de compositionsi dominanceder fluor. (fraduit par la R6daction) Mots-cMs:norbergite, groupe de la humite, affinement de la structure,donn6es de microsonde6lectotrique, hydrogine.
    [Show full text]
  • Crystal Chemistry of the Humite Minerals
    CRYSTAL CHEMISTRY OF THE HUMITE MINERALS by Norris William Jones Thesis submitted to the Graduate Faculty of the Virginia Polytechnic Institute in partial fulfillment for the degree of DOCTOR OF PHILOSOPHY in Geological Sciences APPROVED: Chairman, P. H. Ribbe G. V. Gibbs R. V. Dietrich "T W. D. Lo-.;:;y J. W. Murray June, 1968 Blacksburg, Virginia TABLE OF CONTENTS Page ·Acknowledgements . •• iv List of Tables . v List of Figures • . • •• vi INTRODUCTION . • . • . 1 CRYSTAL STRUCTURES OF THE HUMITES . 4 General . • . • . 4 Comparison of the humite minerals and olivine . 9 Morphotropy . •• 16 Epitaxial intergrowths and twinning . •• 17 Choice of space group and crystallographic axes • 20 CHEMISTRY OF THE HUMITE MINERALS •• . •• 24 Composition . .. •• 24 Compositional variation . • 29 Stoichiometric considerations . • • 32 Electron microprobe analyses . • 38 RELATIONSHIP BETWEEN COMPOSITION AND CELL PARAMETERS •• • 49 ' . (Fe + Mn) for Mg. • • • • • • • • • • • • • • • • . • • 49 Ti for Mg •••• . • • • 52 (OH,F) for 0 . • 52 SUMMARY AND CONCLUSIONS . • •• 55 APPENDIX A: Chemical analyses of the humite minerals • • • 57 APPENDIX B: Calculations of OH, -0, and stoichiometric ratios • 72 APPENDIX C: Microprobe techniques • ~ • • • • • • • • • • • • • 75 ii iii Page Operating conditions • • • • • • • • • • • • • • 76 Data corrections • • • • • • • • • • • • • • • • • 77 Drift. • • • • • • • • • • • • • 80 Dead time. • • • • • • • • • • • • • • • • 80 Background . • • • • • • • • • • • . 81 Mass absorption. • • • • • • • • . 81 Atomic number.
    [Show full text]