Nifontovite and olshanskyite from Fuka, Okayama Prefecture, Japan

1994 ◽  
Vol 58 (391) ◽  
pp. 279-284 ◽  
Author(s):  
Isao Kusachi ◽  
Chiyoko Henmi

AbstractNifontovite and olshanskyite, two rare hydrous calcium borate minerals, have been found in crystalline limestone near gehlenite-spurrite skarns at Fuka, Okayama Prefecture. Nifontovite occurs as aggregates of tabular crystals up to 5 cm long and 1.5 cm wide, and rarely as euhedral crystals up to 1 mm long. Olshanskyite occurs as anhedral masses, or as micro-twinned platy crystals up to 1 cm long. Wet chemical analyses give the empirical formulae Ca3.052B5.991O6.038(OH)12·1.96H2O and Ca2.888B3.997(OH)18 on the basis of O = 20 for nifontovite and OH=18 for olshanskyite, respectively. The formulae are consistent with those from type localities.The X-ray powder data for these minerals were determined with accuracy. The unit cell parameters of nifontovite agree closely with those published previously. X-ray studies show that olshanskyite is triclinic with the possible space group P1̄ or P1 and a = 9.991(5), b = 14.740(11), c = 7.975(3) Å, α = 94.53(4), β = 69.08(3), γ = 112.44(5)° and Z = 3. The density 2.19 g cm−3 (meas.) obtained for olshanskyite agrees with the estimated ideal value 2.31 g cm−3 (calc.). Nifontovite was formed by hydrothermal alteration of an anhydrous borate, and olshanskyite was formed by hydrothermal alteration of nifontovite and the anhydrous borate.

1995 ◽  
Vol 59 (396) ◽  
pp. 549-552 ◽  
Author(s):  
I. Kusachi ◽  
C. Henmi ◽  
S. Kobayashi

AbstractTakedaite, Ca3B2O6, has been found in crystalline limestone near gehlenite−spurrite skarns at Fuka, Okayama Prefecture. It occurs as aggregates of granular crystals up to 0.8 mm long and 0.3 mm wide. The mineral is associated with nifontovite, olshanskyite, pentahydroborite, frolovite, sibirskite, calcite and an unidentified mineral, is white or pale gray, and has a vitreous luster. Takedaite is trigonal with space group of Rc, a = 8.638(1), c = 11.850(2)Å, Z = 6. The strongest lines in the X-ray powder pattern [d in A(I)(hkl)] are 2.915(100)(113), 1.895(75)(223), 2.756(61)(104), 2.493(44)(300), 2.044(21) (214,131), 2.160(19)(220), 1.976(18)(006), 1.549(12)(306). The Vickers microhardness is 478 kg mm−2 and the Mohs hardness 4.5. The density is 3.10(2) g cm−3 (meas.) and 3.11 g cm−3 (calc.). Wet chemical analyses give the values CaO 71.13%, B2O3 28.41%, ig. loss 0.14%, and total 99.68%. The empirical formula calculated on the basis of O = 6 is Ca3.053B1.965O6, with the simplified formula of Ca3B2O6.


2012 ◽  
Vol 76 (7) ◽  
pp. 2773-2783 ◽  
Author(s):  
F. Demartin ◽  
I. Campostrini ◽  
C. Castellano ◽  
C. M. Gramaccioli ◽  
M. Russo

AbstractThe new minerals d'ansite-(Mn), Na21Mn2+(SO4)10Cl3, and d'ansite-(Fe), Na21Fe2+(SO4)10Cl3, occur as encrustations in fumaroles at Vesuvius, Naples, Italy and La Fossa crater, Vulcano, Aeolian Islands, Italy, respectively. Both minerals are cubic and crystallize in space group I3d. D'ansite-(Mn) forms colourless translucent tristetrahedral crystals up to 0.2 mm on edge; d'ansite-(Fe) forms aggregates of colourless to white complex isometric crystals of about the same size. Chemical analyses obtained by energy-dispersive spectrometry on an electron microprobe gave the following mean compositions: d'ansite-(Mn), Na2O 39.37, MnO 3.46, MgO 0.13, SO3 49.99, Cl 6.36, O=Cl–1.44, total 97.87 wt.%, corresponding to an empirical formula, on the basis of 43 anions, of Na20.61 (Mn2+0.79Mg0.05)Σ0.84S10.13O40.09Cl2.91; and d'ansite-(Fe), Na2O 39.12, FeO 4.18, MgO 0.12, SO3 49.91, Cl 6.81, O=Cl –1.54, total 98.60 wt.%, corresponding to an empirical formula of Na20.42(Fe2+0.94Mg0.05)Σ0.99S10.08O39.89Cl3.11. The six strongest reflections in the X-ray powder diffraction pattern of d'ansite-(Fe) [listed as dobs(Å) (I) (hkl)] are as follows: 2.807(100)(044), 2.570(37)(235), 1.714(29)(129), 3.384(27)(233), 3.113(26)(134), 2.108(15)(237). The unit-cell parameters obtained from single-crystal data are 15.9291(9) and 15.882(3) Å for d'ansite-(Mn) and d'ansite-(Fe), respectively. The structure of both minerals was refined, using single-crystal diffraction data, to final R parameters of 0.0309 and 0.0336 on reflections with I > 2σ(I). The structure contains three independent Na sites, one of which is partially occupied by Mn2+ or Fe2+, two independent sulfate anions and one chlorine site.


2021 ◽  
Vol 29 (2) ◽  
pp. 213-229
Author(s):  
Petr Pauliš ◽  
Libor Hrůzek ◽  
Oldřich Janeček ◽  
Zdeněk Dolníček ◽  
Volker Betz ◽  
...  

A new locality of zeolite minerals occurs on the NE edge of the Jedlka village, at the SE slope of the Hlídka hill, 2 km to W of Benešov nad Ploučnicí (northern Bohemia, Czech Republic). The mineralization is developed in Cenozoic analcime-nepheline tephrite. Ten zeolite mineral species (gmelinite-K, analcime, harmotome, chabazite-Ca, lévyne-Ca, mezolite, natrolite, offretite, phillipsite-K, thomsonite-Ca) were found in small amygdule cavities of tephrite. The most interesting is gmelinite-K, a rare zeolite worldwide, which forms clear, white or slightly yellowish, hexagonal lenticular crystals up to 7 mm, always intergrown with the chabazite-Ca. The unit-cell parameters of gmelinite-K, refined from the powder X-ray data, are a = 13.795 (19), c = 9.811(6) Å and V = 1616.8(3) Å3; its quantitative chemical analyses correspond to the empirical formula (K2.32Ca1.86Sr0.53Na0.20Ba0.19)Σ5.10(Al8.14Si16.01O48)·22H2O.


2020 ◽  
Vol 28 (1) ◽  
pp. 152-160
Author(s):  
Petr Pauliš ◽  
Jiří Svejkovský ◽  
Zdeněk Dolníček ◽  
Petr Matys ◽  
Luboš Vrtiška ◽  
...  

A new occurrence of zeolite mineralization with phillipsite-K, phillipsite-Ca, thomsonite-Ca, natrolite and gonnardite has been discovered in an active basalt quarry in the Libá village near Cheb (Czech Republic). Phillipsites in small cavities form druses of white or colourless crystals up to 1 mm in size. Chemical analyses of phillipsite-K correspond to the empirical formula (K1.85Na1.24Ca0.83Ba0.27Sr0.01)Σ4.20(Al6.28Si10.33O32)·12H2O and phillipsite-Ca to (Ca1.84K1.33Na0.14Ba0.06)Σ3.37(Al5.97Si10.20O32)·12H2O. The unit-cell parameters were refined from the powder X-ray data for phillipsite-Ca as: a 9.924(2), b 14.309(3), c 8.7414(14) Å, β 124.92(2)° and V 1017.8(5) Å3. Thomsonite-Ca forms transparent hemispheric radial aggregates up to 1 cm in size. Its unit-cell parameters refined from the powder X-ray data are a 13.105(5), b 13.857(5), c 13.247(6) Å and V 2266.7(6) Å3 and its chemical analyses correspond to the empirical formula Ca1.79Sr0.18Na1.05(Al4.81 Si5.15)O20·6H2O. Natrolite occurs as snow white hemispheric radial clusters. Its unit-cell parameters refined from the powder X-ray data are a 18.326(7), b 18.569(7), c 6.594(3) Å and V 2243.8(9) Å3 and empirical formula is Na1.60Ca0.05(Al2.08 Si3.02)O10·2H2O. Gonnardite forms colourless or white aggregates of flat acicular crystals up to 2 mm in size. Its unit-cell parameters refined from the powder X-ray data are a 13.221(8), c 6.6233(4) Å and V 1156.9 Å3 and empirical formula is (Na3.14Ca2.21Sr0.02)Σ5.37(Al8.92Si11.41)Σ20.33O40·12H2O.


1989 ◽  
Vol 53 (369) ◽  
pp. 85-87 ◽  
Author(s):  
S. Matsubara ◽  
A. Kato

AbstractChemical analyses of bannisterite from the Kamo mine, Toba City, Mie Prefecture, Japan, give Ba : Ca = 69:31–55:45, yielding the ideal formula with Ba > Ca, i.e. (Ba,Ca)(K,H3O)(Mn2+ · Mg,Fe2+)21 (Si,Al)32(O,OH)92 · nH2O, where Ba > Ca, Mn2+ > Mg, Fe2+,Si ≫ Al, and O > OH. The unit cell parameters calculated after the indexing of the X-ray powder pattern are: a = 22.95, b = 16.52, c = 25.66 Å, β = 94.2°. It occurs as dark brown veinlets cutting massive caryopilite-rhodochrosite ore, which is also cut by veinlets of manganoan chlorite (Mn/(Mg + Mn + Fe) = c. 0.30–0.39) with minor barian orthoclase (Ba/(K+ Ba) = 0.05 ∼ 0.06).


2016 ◽  
Vol 65 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Vladimír Hrazdil ◽  
Stanislav Houzar ◽  
Jiří Sejkora ◽  
Šárka Koníčková ◽  
Lenka Jarošová

Abstract Linarite, PbCu2+(SO4)(OH)2, and associated minerals were studied at new locality near Kletné, where they occur in dump material of historic Ag-Pb mines exploited during the 16th century. Linarite forms thin blue coatings and tiny dark blue crystals (<1 mm in size) in small cavities, in assemblage with cerussite, brochantite and supergene copper sulfides. Mineral was identified by chemical analyses (electron microprobe), Raman spectroscopy and powder X-ray diffraction analysis. Chemical composition of the studied linarite can be expressed by empirical formula Pb0.98Cu1.06(SO4)Σ0.96(OH)2.15 and its refined unit-cell parameters are: a = 9.6944(3), b = 5.6499(2), c = 4.6846(1) Å, ß = 102.669(3)° and V = 250.50(1) Å3. Linarite formed together with other supergene minerals in the oxidation zone of the deposit by weathering of Pb- and Cu-sulphides.


2010 ◽  
Vol 74 (6) ◽  
pp. 1013-1025 ◽  
Author(s):  
V. Bermanec ◽  
N. Tomašić ◽  
Ž. Žigovečki Gobac ◽  
M. Rajić Linarić ◽  
K. Furić

AbstractData on the dehydration of pentahydroborite, CaB2O(OH)6·2H2O and nifontovite, Ca3B6O6(OH)12·2H2O from the Fuka mine, Japan are presented. Critical temperatures of the dehydration of the borates were determined by thermogravimetric analysis/differential thermal analysis measurements. The untreated mineral samples and their heating products were investigated by X-ray diffraction and Raman spectroscopy. Upon dehydration, both minerals decompose and undergo amorphization, and at greater temperatures crystallize as an orthorhombic calcium borate, CaB2O4 (Pnca). The dehydration paths of the two minerals are different, with nifontovite showing a greater resistance to decomposition and amorphization than pentahydroborite. Differences in the dehydration processes are related to the residuals of the water content and structural accommodation of the borate polyanion.


2021 ◽  
Vol 29 (1) ◽  
pp. 164-177
Author(s):  
Petr Pauliš ◽  
Libor Hrůzek ◽  
Oldřich Janeček ◽  
Zdeněk Dolníček ◽  
Luboš Vrtiška ◽  
...  

A new locality of böhmite and zeolite minerals, called „Soutěsky above the quarry“, occurs near the quarry „Soutěsky“ on the SW slope of the Hlídka hill, eastward of the Soutěsky village, about 5 km SW od the town of Děčín (Czech Republic). The mineralization is bound to vugs of Cenozoic volcanics. Böhmite forms mostly whitish to brownish hemispherical to spherical clusters up to 5 mm in size. The unit-cell parameters of böhmite, refined from the X-ray powder data, are a 2.871 (3), b 12.216(9), c 3.699(4) Å and V 129.7(2) Å3. Chemical analyses correspond to the empirical formula (Al0.92 Si0.06)Σ0.98O(OH). The following zeolites have been found in association with böhmite: thomsonite-Ca, phillipsite-K, gismondine, chabazite-Ca and analcime, as well as calcite. Minerals crystallized in following succession: calcite I → phillipsite-K → böhmite → calcite II → thomsonite-Ca → gismondine → calcite III. Independently, (older) analcime and (younger) chabazite-Ca occur. These minerals probably crystallized from low tempered solutions, enriched in Al ions and alkalies, the source of which can be found in altered rock-forming alumosilicates (analcime, nepheline).


2020 ◽  
Vol 28 (2) ◽  
pp. 359-363
Author(s):  
Luboš Vrtiška ◽  
Petr Pauliš ◽  
Jiří Čejka ◽  
Radana Malíková ◽  
Zdeněk Dolníček ◽  
...  

A very rare bismuth sulphate, riomarinaite, was found in an old abandoned shaft on a Sn-W deposit Cínovec near Teplice, Northern Bohemia. This is first occurrence of this generally very rare mineral in the Czech Republic. Riomarinaite forms grey and blue acicular and columnar crystals up to 30 μm in size in association with native bismuth and bismuthinite. Riomarinaite is monoclinic, space group P21/n, the unit-cell parameters refined from X-ray powder diffraction data are: a 6.0091(19), b 13.328(5), c 6.483(3) Å, β 112.91(5)˚ and V 478.3(3) Å3. Chemical analyses of riomarinaite correspond to the empirical formula (Bi1.10Ca0.02)Σ1.12[(SO4)0.92(MoO4)0.08]Σ1.00(OH)1.33·H2O on the basis of S + Mo = 1 apfu. Raman bands connected with vibrations of (OH)-, H2O, (SO4)2- groups, Bi-O bonds and lattice modes were observed in the Raman spectrum of riomarinaite.


2020 ◽  
Vol 28 (2) ◽  
pp. 454-465
Author(s):  
Jiří Sejkora ◽  
Bohuslav Bureš

An interesting mineral association of Cu arsenates was found at abandoned ore stope at the Geschieber vein - north at the Daniel level of the Svornost mine, the Jáchymov ore district, Krušné hory, Czech Republic. Tangdanite forms thin tabular crystals up to 3 mm in size and coatings and fine crystalline aggregates on the area up to some cm2. It has light green, bluish-green to emerald green color and perfect cleavage. It is monoclinic, space group C2/c, the unit-cell parameters refined from X-ray powder diffraction data are: a 54.335(12), b 5.579(2), c 10.459(2) Å, β 95.42(3)° and V 3156(2) Å3; its chemical analyses correspond to the empirical formula Ca1.99(Cu8.72Zn0.09Ni0.04Al0.04)Σ8.89[(AsO4)3.83 (PO4)0.14(SiO4)0.03]Σ4.00(SO4)0.41(OH)8.97·9H2O on the basis As+P+Si+V = 4 apfu. The results of Raman and infrared spectroscopy confirmed an absence of carbonate group in studied tangdanite. K-rich lavendulan was found as a relatively abundant sky blue crusts and coatings on the area up to some cm2 and hemispherical aggregates with a radial structure or rarely as a group of thin tabular crystals up to 0.2 mm in size. It is monoclinic, space group P21/n, the unit-cell parameters refined from X-ray powder diffraction data are: a 10.081(12), b 19.469(12), c 10.033(9) Å, β 90.32° and V 1969(2) Å3; its chemical analyses correspond to the empirical formula (Na0.63K0.16)Σ0.79Ca1.12(Cu4.82Al0.01)Σ4.83[(AsO4)3.86(PO4)0.07 (SO4)0.06(SiO4)0.01]Σ4.00Cl0.96·5H2O on the basis As+P+V+Si+S = 4 apfu. Olivenite occurs as olive green spherical aggregates with radial structure up to 8 mm in size and rarely as groups of acicular crystals in association with strashimirite and köttigite. It is orthorhombic, space group Pnnm, the unit-cell parameters refined from X-ray powder diffraction data are: a 8.6204(10), b 8.2332(9), c 5.9337(11) Å and V 421.13(7) Å3; its chemical analyses correspond to the empirical formula (Cu1.94Ni0.01Al0.01)Σ1.96[(AsO4)0.97(VO4)0.02(PO4)0.01]Σ1.00(OH)0.93 on the basis As+V+P = 1 apfu. Strashimirite forms there light green crystalline coatings on the area up to several cm2 and spherical aggregates with a radial structure in association with olivenite and lavendulan. Strashimirite is probably monoclinic, space group P2, the unit-cell parameters refined from X-ray powder diffraction data are: a 9.991(9), b 18.466(9), c 8.986(8) Å, β 96.5(2)° and V 1574(3) Å3; its chemical analyses correspond to the empirical formula (Cu7.83Ni0.18Ca0.09Zn0.06Co0.02Al0.02)Σ8.20 [(AsO4)3.81(PO4)0.07 (SO4)0.07(VO4)0.03(SiO4)0.02]Σ4.00 (OH)4.45·5H2O on the basis As+P+Si+V+S = 4 apfu. Chalcophyllite was found as rare emerald green thin tabular crystals up to 0.5 mm in size and crystalline aggregates. Its chemical composition is possible to express on the basis As+S+P+Si = 7 apfu by the empirical formula Cu17.83Al1.97[(AsO4)4.00(PO4)0.09]Σ4.09[(SO4)2.80(SiO4)0.11]Σ2.91 (OH)23.27·36H2O. Brochantite, devilline, köttigite, erythrite and gypsum were also found in the association with Cu arsenates. The origin of the described mineral association is connected with (sub)recent weathering of primary ore minerals (tennantite, sphalerite, nickelskutterudite) in relatively dry conditions of abandoned mine adits.


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