Spring 2003 Gems & Gemology
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Chemical Composition of Mn-And Cl-Rich Apatites from the Szklary
minerals Article Chemical Composition of Mn- and Cl-Rich Apatites from the Szklary Pegmatite, Central Sudetes, SW Poland: Taxonomic and Genetic Implications Adam Szuszkiewicz 1,* ID , Adam Pieczka 2, Bozena˙ Goł˛ebiowska 2, Magdalena Duma ´nska-Słowik 2 ID , Mariola Marszałek 2 and Eligiusz Szeł˛eg 3 1 Institute of Geological Sciences, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław, Poland 2 Department of Mineralogy, Petrography and Geochemistry, AGH University of Science and Technology Mickiewicza 30, 30-059 Kraków, Poland; [email protected] (A.P.); [email protected] (B.G.); [email protected] (M.D.-S.); [email protected] (M.M.) 3 Department of Geochemistry, Mineralogy and Petrography, Faculty of Earth Sciences, University of Silesia, B˛edzi´nska60, 41-200 Sosnowiec, Poland; [email protected] * Correspondence: [email protected] Received: 6 July 2018; Accepted: 9 August 2018; Published: 14 August 2018 Abstract: Although calcium phosphates of the apatite group (apatites) with elevated contents of Mn are common accessory minerals in geochemically evolved granitic pegmatites, their Mn-dominant M1 M2 X analogues are poorly studied. Pieczkaite, Mn2 Mn3(PO4)3 Cl, is an exceptionally rare Mn analogue of chlorapatite known so far from only two occurrences in the world, i.e., granitic pegmatites at Cross Lake, Manitoba, Canada and Szklary, Sudetes, SW Poland. In this study, we present the data on the compositional variation and microtextural relationships of various apatites highly enriched in Mn and Cl from Szklary, with the main focus on compositions approaching or attaining the stoichiometry of pieczkaite (pieczkaite-like apatites). -
The Journal of Gemmology Data Depository Photomicrographs To
The Journal of Gemmology Data Depository Photomicrographs to accompany the article: Hänni H.A., Brunk R. and Franz L. 2021. An investigation of grinding hardness of some ornamental stones. Journal of Gemmology, 37(6), 2021, 632–643, https://doi.org/10.15506/JoG.2021.37.6.632. The following photomicrographs of thin sections of the samples were made with a Leica DFC490 camera mounted on a Leica DMRD polarising microscope with transmitted light. For each sample, figure A shows the sample in plane-polarised light (II Pol.) and figure B with crossed polarisers (X Pol.); the sample numbers correspond to those in the article. Photomicrographs © L. Franz. 1 1 Aventurine quartz, green: Foliated matrix with aligned quartz (Qz) grains, fuchsite (Fu) tablets and accessory zircon (Zrn). 2 2 Aventurine quartz, orangey red: Mylonitic fabric with quartz (Qz) ribbons and recrystallized grains as well as intergrowths of muscovite with hematite (Ms & Hem). 3 3 Chalcedony, light grey: Intensely interlocked chalcedony (Chc) crystals with random orientation. 4 4 Chrysoprase: In a matrix of tiny chalcedony (Chc) and quartz (Qz) crystals, larger quartz aggregates occur. In microfractures, palisade-shaped chalcedony crystals and quartz grains formed. 5 5 Dumortierite: A banded texture with layers rich in dumortierite (Dum), dumortierite and quartz (Dum & Qz), quartz (Qz) and tourmaline (Tur). 6 6 Granite: The holocrystalline fabric is made up of subhedral plagioclase (Pl), orthoclase (Or), biotite (Bt) and anhedral quartz (Qz). 7 7 Green quartz: A granoblastic texture made up of large quartz (Qz) crystals as well as a microfolded layer of fuchsite (Fu). 8 8 Heliotrope (bloodstone): Green, brown and colourless accumulations of chalcedony (Chc) are recognizable. -
Phase Equilibria and Thermodynamic Properties of Minerals in the Beo
American Mineralogist, Volwne 71, pages 277-300, 1986 Phaseequilibria and thermodynamic properties of mineralsin the BeO-AlrO3-SiO2-H2O(BASH) system,with petrologicapplications Mlnx D. B.qnroN Department of Earth and SpaceSciences, University of California, Los Angeles,Los Angeles,California 90024 Ansrru,cr The phase relations and thermodynamic properties of behoite (Be(OH)r), bertrandite (BeoSirOr(OH)J, beryl (BerAlrSiuO,r),bromellite (BeO), chrysoberyl (BeAl,Oo), euclase (BeAlSiOo(OH)),and phenakite (BerSiOo)have been quantitatively evaluatedfrom a com- bination of new phase-equilibrium, solubility, calorimetric, and volumetric measurements and with data from the literature. The resulting thermodynamic model is consistentwith natural low-variance assemblagesand can be used to interpret many beryllium-mineral occurTences. Reversedhigh-pressure solid-media experimentslocated the positions of four reactions: BerAlrSiuO,,: BeAlrOo * BerSiOo+ 5SiO, (dry) 20BeAlSiOo(OH): 3BerAlrsi6or8+ TBeAlrOo+ 2BerSiOn+ l0HrO 4BeAlSiOo(OH)+ 2SiOr: BerAlrSiuO,,+ BeAlrOo+ 2H2O BerAlrSiuO,,+ 2AlrSiOs : 3BeAlrOa + 8SiO, (water saturated). Aqueous silica concentrationswere determined by reversedexperiments at I kbar for the following sevenreactions: 2BeO + H4SiO4: BerSiOo+ 2H2O 4BeO + 2HoSiOo: BeoSirO'(OH),+ 3HrO BeAlrOo* BerSiOo+ 5H4Sio4: Be3AlrSiuOr8+ loHro 3BeAlrOo+ 8H4SiO4: BerAlrSiuOrs+ 2AlrSiO5+ l6HrO 3BerSiOo+ 2AlrSiO5+ 7H4SiO4: 2BerAlrSiuOr8+ l4H2o aBeAlsioloH) + Bersio4 + 7H4sio4:2BerAlrsiuors + 14Hro 2BeAlrOo+ BerSiOo+ 3H4SiOo: 4BeAlSiOr(OH)+ 4HrO. -
Rhodochrosite Gems Unstable Colouration of Padparadscha-Like
Volume 36 / No. 4 / 2018 Effect of Blue Fluorescence on the Colour Appearance of Diamonds Rhodochrosite Gems The Hope Diamond Unstable Colouration of in London Padparadscha-like Sapphires Volume 36 / No. 4 / 2018 Cover photo: Rhodochrosite is prized as both mineral specimens and faceted stones, which are represented here by ‘The Snail’ (5.5 × 8.6 cm, COLUMNS from N’Chwaning, South Africa) and a 40.14 ct square-cut gemstone from the Sweet Home mine, Colorado, USA. For more on rhodochrosite, see What’s New 275 the article on pp. 332–345 of this issue. Specimens courtesy of Bill Larson J-Smart | SciAps Handheld (Pala International/The Collector, Fallbrook, California, USA); photo by LIBS Unit | SYNTHdetect XL | Ben DeCamp. Bursztynisko, The Amber Magazine | CIBJO 2018 Special Reports | De Beers Diamond ARTICLES Insight Report 2018 | Diamonds — Source to Use 2018 The Effect of Blue Fluorescence on the Colour 298 Proceedings | Gem Testing Appearance of Round-Brilliant-Cut Diamonds Laboratory (Jaipur, India) By Marleen Bouman, Ans Anthonis, John Chapman, Newsletter | IMA List of Gem Stefan Smans and Katrien De Corte Materials Updated | Journal of Jewellery Research | ‘The Curse Out of the Blue: The Hope Diamond in London 316 of the Hope Diamond’ Podcast | By Jack M. Ogden New Diamond Museum in Antwerp Rhodochrosite Gems: Properties and Provenance 332 278 By J. C. (Hanco) Zwaan, Regina Mertz-Kraus, Nathan D. Renfro, Shane F. McClure and Brendan M. Laurs Unstable Colouration of Padparadscha-like Sapphires 346 By Michael S. Krzemnicki, Alexander Klumb and Judith Braun 323 333 © DIVA, Antwerp Home of Diamonds Gem Notes 280 W. -
Elimination of Ferric Ion Effect on Separation Between Kyanite and Quartz Using Citric Acid As Regulator
minerals Article Elimination of Ferric Ion Effect on Separation between Kyanite and Quartz Using Citric Acid as Regulator Yanping Niu 1, Ya Li 1, Haoran Sun 2,*, Chuanyao Sun 3, Wanzhong Yin 2 and Hongfeng Xu 4 1 Heilongjiang Province Geology Ore Test and Application Institute, Harbin 150000, China; [email protected] (Y.N.); [email protected] (Y.L.) 2 College of Resources and Civil Engineering, Northeastern University, Shenyang 110816, China; [email protected] 3 State Key Laboratory of Mineral Processing, BGRIMM Technology Group, Beijing 100160, China; [email protected] 4 Heilongjiang Mining Group Co., Ltd., Harbin 150000, China; [email protected] * Correspondence: [email protected]; Tel.: +86-188-4250-4743 Abstract: Ferric ions produced during grinding influence the flotation separation between kyanite and quartz adversely. In this study, citric acid was used as a regulator to eliminate the effect of ferric ions on the separation of kyanite from quartz with sodium oleate (NaOL) as a collector. The microflotation test results indicated that the quartz was selectively activated by FeCl3 and maintained significant quartz recovery. However, the citric acid could selectively eliminate the effect of ferric ions on the quartz and minimally influenced the kyanite. Contact angle tests demonstrated that FeCl significantly increased the interaction between NaOL and quartz, resulting in the high 3 hydrophobicity of quartz, and the addition of citric acid made the quartz surface hydrophilic again but slightly influenced the kyanite. Fourier-transform infrared spectroscopy showed that FeCl Citation: Niu, Y.; Li, Y.; Sun, H.; Sun, 3 C.; Yin, W.; Xu, H. Elimination of facilitated NaOL adsorption onto the quartz surface, and the addition of citric acid eliminated the Ferric Ion Effect on Separation activation of FeCl3 on the quartz, resulting in the nonadsorption of NaOL onto the quartz surface. -
Pearls and Organic Gemstones
Pearls and Organic Gemstones INTRODUCTION Pearls were probably the first discovered gems of significance. Because they need no cutting or treatment to enhance their beauty and are rare natural occurrences, they have most likely always been highly esteemed. Organic gemstones are anything created by living processes. We have looked at amber in the past, but bone, teeth (such as ivory), and shells all have some value and are used today as gemstones. Pearls in General A pearl is grown by a mollusk (a bivalve such as a clam, oyster, or mussel or snail [single shell = valve]) in response to an irritant. Bivalves (two shelled mollusks) that secrete pearls live in both fresh‐ and saltwater. The irritant in most cases is a parasite (though it could be a grain of sand or other object). The parasite, a worm or other creature, is walled off by a secretion of calcium carbonate and protein. The calcium carbonate is the same as the inorganic material that makes stalactites in caves, and the protein is called conchiolin. The combination of these two substances (calcium carbonate and protein) makes the pearl's nacre (Nacre is also called mother of pearl). The nacre is a lustrous deposit around the irritant and forms concentric layers (overlapping circles). Many concentric layers of nacre build up over a period of a few years creating a pearl. The internal pattern is much like that seen in a jawbreaker. The layers create a sheen or luster that has iridescence and is described as both pearly luster and if colors of the rainbow are present, the pearl's orient. -
Nautiloid Shell Morphology
MEMOIR 13 Nautiloid Shell Morphology By ROUSSEAU H. FLOWER STATEBUREAUOFMINESANDMINERALRESOURCES NEWMEXICOINSTITUTEOFMININGANDTECHNOLOGY CAMPUSSTATION SOCORRO, NEWMEXICO MEMOIR 13 Nautiloid Shell Morphology By ROUSSEAU H. FLOIVER 1964 STATEBUREAUOFMINESANDMINERALRESOURCES NEWMEXICOINSTITUTEOFMININGANDTECHNOLOGY CAMPUSSTATION SOCORRO, NEWMEXICO NEW MEXICO INSTITUTE OF MINING & TECHNOLOGY E. J. Workman, President STATE BUREAU OF MINES AND MINERAL RESOURCES Alvin J. Thompson, Director THE REGENTS MEMBERS EXOFFICIO THEHONORABLEJACKM.CAMPBELL ................................ Governor of New Mexico LEONARDDELAY() ................................................... Superintendent of Public Instruction APPOINTEDMEMBERS WILLIAM G. ABBOTT ................................ ................................ ............................... Hobbs EUGENE L. COULSON, M.D ................................................................. Socorro THOMASM.CRAMER ................................ ................................ ................... Carlsbad EVA M. LARRAZOLO (Mrs. Paul F.) ................................................. Albuquerque RICHARDM.ZIMMERLY ................................ ................................ ....... Socorro Published February 1 o, 1964 For Sale by the New Mexico Bureau of Mines & Mineral Resources Campus Station, Socorro, N. Mex.—Price $2.50 Contents Page ABSTRACT ....................................................................................................................................................... 1 INTRODUCTION -
Ajoite: New Data
American Mineralogist, Volume 66, pages 201-203, 1981 Ajoite: new data GEORGE Y. CHAO Department of Geology, Carleton University Ottawa, Ontario Kl S 5B6, Canada Abstract New data show that ajoite is triclinic, PI or pI, a ==13.637, b ==14.507, c ==13.620A, a == 107.16, f3 = 105.45, y = 110.57°; Z ==3. The mineral is biaxial positive, 2V ==80°, a ==1.550, f3 = 1.583, y = 1.641 (in Na light); pleochroic: X = very light bluish green, Y -- Z ==brilliant bluish green. {010} cleavage is perfect. The orientation of the principal vibration directions is defined by the spherical coordinates X(26.5°, 80°), Y(118°, 79°), Z(-104.5°, 15°). The ex- tinction angle c: Z' on (0 I0) is 150. Electron microprobe and chemical analyses gave Si02 41.2, Al203 3.81, CuO 42.2, MnO 0.02, FeO 0.11, CaO 0.04, Na20 0.84, K20 2.50, H20 (TGA to 1000°C) 8.35, sum 99.07 wt.%. The analysis corresponds to (Ko.70NaO.36Cao.Ol)(CUt,.97 Feo.o2)Alo.98Si9.oo024(OH)6'3.09H20 or ideally, (K,Na)Cu7AISi9024(OH)6' 3H20. TGA showed a two-stage dehydration; 50% of the total water was released between 70° and 425°C and the rest between 4250 and 800°C. Half of the water is zeolitic in nature. Introduction are always present. The termination on c may be ei- Ajoite, first described by Schaller and Vlisidis ther {001} or {203} or both. (1958) from Ajo, Pima County, Arizona, was thought to be monoclinic on the basis of optical studies. -
High-Pressure Crystal Chemistry of Beryl (Beralrsi.Otr) and Euclase
American Mineralogist, Volume 71, pages 977-984, 1986 High-pressurecrystal chemistry of beryl (BerAlrSi.Otr) and euclase(BeAlSiO4OH) Rosnnr M. HaznN, ANonpw Y. Au, Llnnv W. FrNcnn GeophysicalLaboratory, CarnegieInstitution of Washington, 2801 Upton Street,N.W., Washington, D.C. 20008 Ansrnlcr Compressibilities and high-pressurecrystal structures of beryl and euclasehave beon determined by X-ray methods at severalpressures. Beryl (hexagonal,space group P6/mcc) has nearly isotropic compressibility; linear compressibilitiesperpendicular and parallel to the c axis ateB':1.72 + 0.04 x l0-a kbar-'and B,:2.10 + 0.09 x 10-akbar-'. The correspondingbulk modulus is 1.70 + 0.05 Mbar if the pressurederivative of the bulk modulus K'is assumedto be 4. Euclase(monoclinic, spacegroup P2r/a)has anisotropic compression,with maximum compressibrlity of 2.44 + 0.05 x l0-a kbar-l parallel to the unique monoclinic b axis, and minimum compressibility of 1.50 + 0.03 x 10-a kbar-' approximately parallel to [01]. The intermediate axis of compressionhas a magnitude of 1.96 + 0.05 x lO-akbar-'in the a-c plane.The bulk modulus of euclaseis 1.59 t 0.03 Mbar if K' is assumedto be 4. The bulk moduli ofBe, Al, and Si cation coordination polyhedrain beryl are all consistent with 1.7 Mbar, which is the crystal bulk modulus. Beryl compressionoccurs primarily by shorteningof cation-anion bond distances.In euclase,the 2.3-Mbar polyhedralbulk moduli are significantly greater than the observed 1.6-Mbar crystal modulus. Compression in euclase,particularly along the b crystallographicaxis, results from a combination of poly- hedral compressionand changesin interpolyhedral angles. -
Some Uncommon Sapphire “Imitations”: Blue Co-Zirconia, Kyanite & Blue Dumortierite Dr Michael S
Some Uncommon Sapphire “Imitations”: Blue Co-zirconia, Kyanite & Blue Dumortierite Dr Michael S. Krzemnicki Swiss Gemmological Institute SSEF [email protected] 筆者滙報數個瑞士珠寶研究院(SSEF)近期收到 in the ring showed a negative RI reading 要求鑑證的藍色寶石,經檢測後確定其中包括 (above 1.79), an isotropic optical character 一些非常罕見的藍寶石模擬石:含錮氧化鋯、 (polariscope) and thus no pleochroism at all. 藍晶石及藍線石等。 Under the microscope, we saw no inclusions, however a slightly greenish reaction under Sapphires are among the most abundant gems the LWSW and there was a weaker similar we receive at the Swiss Gemmological Institute reaction under SWUV lamps. Based on these (SSEF) for testing. From time to time, however, properties and a chemical analysis by X-ray we are quite surprised by the imitations which fluorescence (EDXRF), the blue stone was we find among the goods sent in and this can readily identified as cubic zirconia (ZrO2). then be disappointing news for the clients. In Having seen this artificial product in a wide the following short note, the author presents a range of colours, the author had not previously few uncommon imitations identified recently at seen one of such a saturated and attractive the SSEF. Identification of these imitations is blue. Based on literature (Nassau 1981) the straightforward and should be no problem for analysed traces of cobalt in that stone have any experienced gemmologist. been identified as the colouring element in this specimen. The absorption spectrum of the stone The first case is that of an attractive blue (Fig. 2) – although superposed by several rare faceted stone of approximately 1.4 ct, set in a ring with diamonds (Fig. -
Wickenburgite Pb3caal2si10o27² 3H2O
Wickenburgite Pb3CaAl2Si10O27 ² 3H2O c 2001 Mineral Data Publishing, version 1.2 ° Crystal Data: Hexagonal. Point Group: 6=m 2=m 2=m: Tabular holohedral crystals, dominated by 0001 and 1011 , to 1.5 mm. As spongy aggregates of small, highly perfect f g f g individuals; as subparallel aggregates or rosettes; granular. Physical Properties: Cleavage: 0001 , indistinct. Tenacity: Brittle but tough. Hardness = 5 D(meas.) = 3.85 D(cfalc.) g= 3.88 Fluoresces dull orange under SW UV. Optical Properties: Transparent to translucent. Color: Colorless to white; rarely salmon-pink. Luster: Vitreous. Optical Class: Uniaxial ({). Dispersion: r < v; moderate. ! = 1.692 ² = 1.648 Cell Data: Space Group: P 63=mmc: a = 8.53 c = 20.16 Z = 2 X-ray Powder Pattern: Near Wickenburg, Arizona, USA. 10.1 (100), 3.26 (80), 3.93 (60), 3.36 (40), 2.639 (40), 5.96 (30), 5.04 (30) Chemistry: (1) (2) SiO2 42.1 40.53 Al2O3 7.6 6.88 PbO 44.0 45.17 CaO 3.80 3.78 H2O 3.77 3.64 Total 101.27 100.00 (1) Near Wickenburg, Arizona, USA. (2) Pb3CaAl2Si10O24(OH)6: [needsnew??formula] Occurrence: In oxidized hydrothermal veins, carrying galena and sphalerite, in quartz and °uorite gangue (near Wickenburg, Arizona, USA). Association: Phoenicochroite, mimetite, cerussite, willemite, crocoite, duftite, hemihedrite, alamosite, melanotekite, luddenite, ajoite, shattuckite, vauquelinite, descloizite, laumontite. Distribution: In the USA, in Arizona, at several localities south of Wickenburg, Maricopa Co., including the Potter-Cramer property, Belmont Mountains, and the Moon Anchor mine; on dumps at a Pb-Ag-Cu prospect in the Artillery Peaks area, Mohave Co.; and in the Dives (Padre Kino) mine, Silver district, La Paz Co. -
Scandiobabingtonite, a New Mineral from the Baveno Pegmatite
American Mineralogist, Volume 83, pages 1330-1334, 1998 Scandiobabingtonite,a new mineral from the Bavenopegmatite, Piedmont, Italy Ploro ORl.tNnIrr'* Ma,nco PasERorr and GrovlNNa Vn,zzllrNr2 rDipartimento di Scienzedella Terra, Universitd di Pisa, Via S. Maria 53,1-56126 Pisa, Italy '?Dipartimento di Scienzedella Terra, Universitd di Modena, Via S Eufemia 19, I-41 100 Modena, Italy Ansrntcr Scandiobabingtonite,ideally Ca,(Fe,*,Mn)ScSi,O,o(OH) is the scandium analogue of babingtonite; it was found in a pegmatitic cavity of the Baveno granite associatedwith orthoclase, albite, muscovite, stilbite, and fluorite. Its optics are biaxial (+) with 2V : : ^v: 64(2)",ct 1.686(2),P: 1.694(3), 1.709(2).D-"." : 3.24(5)slcm3, D.",.:3.24 sl cm3, and Z : 2. Scandiobabingtoniteis colorless or pale gray-green, transparent,with vitreous luster. It occurs as submillimeter sized, short, tabular crystals, slightly elongated on [001],and characterizedby the associationof forms {010}, {001}, {110}, {110}, and {101}. It occurs also as a thin rim encrustingsmall crystals of babingtonite.The strongest lines in the X-ray powder pauern are at2.969 (S), 2.895 (S), 3.14 (mS), and 2.755 (mS) 4. fn" mineralis triclinic, ipu.. g.oup PT, with a : 7.536(2),b : 1L734(2),c : 6.t48(Z) A, : 91.10(2), : 93.86(2), : lO+.S:(2)'. Scandiobabingtoniteis isostructural " B r with babingtonite, with Sc replacing Fe3* in sixfold coordination, but no substitution of Fer* by Sc takes place. Due to the lack of a suitably large crystal of the new species, such a replacementhas been confirmed by refining the crystal structure of a Sc-rich babingtonite (final R : O.O47)using single-crystal X-ray diffraction (XRD) data.