Blue Tint Research Articles

Tl-bearing sulfosalt from the Lengenbach quarry, Binn Valley, Switzerland: Philrothite, TlAs3S5

AbstractPhilrothite, ideally TlAs3S5, is a new mineral from the Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs as very rare crystals up to 200 mm across on realgar associated with smithite, rutile and sartorite. Philrothite is opaque with a metallic lustre and shows a dark brown streak. It is brittle; the Vickers hardness (VHN25) is 128 kg/mm2(range: 120–137) (Mohs hardness of 3–3½). In reflected light philrothite is moderately bireflectant and weakly pleochroic from dark grey to light grey. Under crossed polars it is anisotropic with grey to bluish rotation tints. Internal reflections are absent. Reflectance percentages for the four COM wavelengths (RminandRmax) are: 26.5, 28.8 (471.1 nm), 25.4, 27.2 (548.3 nm), 24.6, 26.3 (586.6 nm) and 24.0, 25.1 (652.3 nm), respectively.Philrothite is monoclinic, space groupP21/c, witha= 8.013(2),b= 24.829(4),c= 11.762(3) Å,β= 132.84(2)°,V= 1715.9(7) Å3,Z= 8. It represents theN= 4 homologue of the sartorite homologous series. In the crystal structure [R1= 0.098 for 1217 reflections withI> 2σ(I)], Tl assumes tricapped prismatic sites alternating to form columns perpendicular to the b axis. Between the zigzag walls of Tl coordination prisms, coordination pyramids of As(Sb) form diagonally-oriented double layers separated by broader interspaces which house the lone electron pairs of these elements.The eight strongest calculated powder-diffraction lines [din Å(I/I0) (hkl)] are: 12.4145 (52) (020); 3.6768 (100) (61); 3.4535 (45) (131); 3.0150 (46) (53); 2.8941 (52) (81); 2.7685 (76) (230); 2.7642 (77) (34); 2.3239 (52) (092). A mean of five electron microprobe analyses gave Tl 26.28(12), Pb 6.69(8), Ag 2.50(4), Cu 0.04(2), Hg 0.07(2), As 32.50(13), Sb 3.15(3), S 26.35(10), total 97.58 wt.%, corresponding, on the basis of a total of nine atoms, to (Tl0.789Pb0.198)∑=0.987(As2.662Sb0.159Ag0.142Cu0.004Hg0.002)∑=2.969S5.044. The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (2013-066) and named for Philippe Roth (b. 1963), geophysicist and well known mineral expert on the Lengenbach minerals for more than 25 years.

Alburnite, Ag8GeTe2S4, a new mineral species from the Rosia Montana Au-Ag epithermal deposit, Apuseni Mountains, Romania

Alburnite, ideally Ag 8 GeTe 2 S 4 , was discovered in the Cârnicel vein from the Roşia Montana epithermal Au-Ag ore deposit, Apuseni Mountains, Romania. The new mineral is associated with tetrahedrite, galena, pyrite, sphalerite, chalcopyrite, and tellurides (hessite, altaite, and sylvanite). Associated gangue minerals are rhodochrosite, quartz, calcite, and rhodonite. Alburnite was observed only at the microscopic scale as rounded to sub-rounded grains, veinlets or irregular inclusions hosted mainly by tetrahedrite, hessite, and rhodochrosite. Due to the small size of alburnite grains observed so far it was not possible to determine some macroscopic properties; reported properties are based on microscopic observations. The mineral has a metallic luster and is opaque. It is non-fluorescent and has an estimated Mohs hardness of 4. The mineral shows no cleavage. Density could not be measured because of the small grain size, but calculated density based on the empirical formula is 7.828 g/cm3. In plane-polarized light in air, alburnite is gray-blue with a bluish tint. It shows no pleochroism or bireflectance in air. Between crossed polars alburnite is isotropic and internal reflections have not been observed in air. The mineral decomposes in intense light. Reflectance minimum values in air (in percents) are: 470 nm 29.70; 546 nm 28.00; 589 nm 27.35; 650 nm 26.95. The average chemical composition based on 18 electron microprobe analyses from 9 different grains in one polished section is (in wt%): Ag 65.49, Ge 4.82, Te 20.16, S 9.66, total 100.13. The ideal formula of alburnite, Ag 8 GeTe 2 S 4 , based on 15 apfu requires Ag 65.43, Ge 5.50, Te 19.35, S 9.72, total 100.00 wt%. Features of the crystal structure of alburnite were determined based on electron backscattered diffraction and transmission electron microscopy. Alburnite is cubic, space group F 43 m , with unit-cell parameters a = 10.4(1) Å, V = 1125(30) Å 3 , Z = 4. The strongest eight calculated XRD lines [ d in Å( I )( hkl )] are: 6.004(67)(111), 3.136(48)(113), 3.002(100)(222), 2.600(26)(004), 2.123(33)(224), 2.002(61)(115), 1.838(76)(044), and 1.644(12)(026). The name of the new mineral alburnite is derived from the Latin name of the locality. Roşia Montana Au-Ag deposit was known during the Roman period as Alburnus Maior . The mineral and the mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification, IMA 2012-073.

The effect of tinted spectacle lenses on contrast sensitivity and colour vision

Aim: Spectacle wearers often prefer tintedlenses to clear or non-tinted lenses for their protection against harmful radiation, improved cos-mesis, enhancement of visual performance and effects on colour vision. Among the available tinted lenses on the market blue, brown and grey tinted spectacle lenses are popular with varying gradesranging from A to D. Due to reduced transmission of light through such lenses, the optical system of the eyes and the environmental vision may be temporarily altered. Colour vision (CV) and con-trast sensitivity (CS) are important aspects of this altered visual world. This study investigated the effect of spectacle lenses of varying grades of tint on CS and CV.Method: The study adopted a pre- and postest research design and a sample of 90 participants were selected from the University of KwaZulu-Natal student population using convenience sam-ling. Each participant was screened for patholgy, dyschromatopsia, severe dry eyes (TBUT<5 seconds), and the presence of any more than low metropia. Thereafter each successful participant was tested for CS and CV with their habitual precription and then tested randomly with a white clear) lens (placebo) and tinted (blue, brown, and grey) spectacle lenses made of CR39 material each having grades A, B and C over their habitual state. Light transmission was 85%, 75%, and 50% for grades A, B, and C respectively. The Functional Acuity Contrast Test (FACT) chart and American Optical Hardy, Rand, and Rittler (AO HRR) were used for the assessment of CS and CV respectively.Results: The data was analysed using the Statistical Package of Social Science (SPSS) version18. Compared to the habitual state, contrast sensitivity was enhanced with all the tinted lensesThe greater enhancement was for low spatial frequencies (LSF) and least for high spatial frequencies (HSF). With all tints Grade C had the least enhancement for very HSF. Many subjects showed no change in CV with any of the lensesused. The grey tint showed greater enhancement of CV as the density increases. Blue and brown tints showed a similar trend with grade B enhancing CV the most while grade C resulted in theleast reduction of CV.Conclusion: Grade A, B, and C of blue, brown and grey tinted spectacle lenses do not alter colour vision significantly but for the selected levels of transmission of the tints used, contrast sensitivity can be improved to some extent.

Discoloration of the Esophagus

Question: A 74-year-old white woman with a past medical history of dyslipidemia, irritable bowel syndrome, and gastroesophageal reflux disease presented with abdominal bloating and persistent cough. She had no history of heartburn, dysphagia, or odynophagia. An upper endoscopy was performed. On endoscopy, the esophageal mucosa appeared bulbous with a blue tint. The lesion was 6 cm in size between 18 and 24 cm from the incisors (Figure A, B). The rest of the examination was normal. As part of her evaluation, computed tomography of the neck, chest, and abdomen was performed (Figure C). What is this lesion? Look on page 1501 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. This is a large cavernous esophageal hemangioma. Hemangioma is a rare tumor of the esophagus, representing approximately 3% of benign tumors of the esophagus. Incidence in the population at large was 0.04% in an autopsy study.1Moersch H.J. Harrington S.W. Benign tumor of the esophagus.Ann Otol Rhinol Laryngol. 1944; 53: 800Google Scholar, 2Raza W. Nasir H. Ilahi F. et al.Esophageal haemangioma: a case report and review of literature.J Pak Med Assoc. 2010; 60: 310-311PubMed Google Scholar The patient had a history of irritable bowel syndrome and presented with symptoms of abdominal bloating and cough. Endoscopy was performed to evaluate her symptoms. The patient also had a prior history of gastroesophageal reflux disease and an esophagogastroduodenoscopy had been performed in 2008, which showed a smaller area of blue discoloration in the same location. Computed tomography of the chest was performed with 150 ccs Omnipaque 300 IV contrast. The lungs were clear. There was a low-density, rounded mass measuring approximately 3 × 2 × 3.5 cm adjacent to the esophagus. This was at the level of the aortic arch. Several small calcifications within this structure were consistent with a hemangioma. The mass was relatively well demarcated. No lymphadenopathy was seen. No other masses were identified. No other esophageal lesions were suspected. Esophageal hemangioma is typically asymptomatic, but because of the size of this lesion the patient was sent to a university hospital for further evaluation. The patient and thoracic surgeon elected to follow a conservative treatment plan because her symptoms had resolved. When symptomatic the most common course of treatment is operative resection, but endoscopic resections have also been successful.3Sogabe M. Taniki T. Fukui Y. et al.A patient with esophageal hemangioma treated by endoscopic mucosal resection: a case report and review of the literature.J Med Invest. 2006; 53: 177Crossref PubMed Scopus (20) Google Scholar

Terrywallaceite, AgPb(Sb,Bi)3S6, isotypic with gustavite, a new mineral from Mina Herminia, Julcani Mining District, Huancavelica, Peru

A new mineral species, terrywallaceite, ideally AgPb(Sb,Bi) 3 S 6 , has been found in Mina Herminia, Julcani Mining District, Huancavelica, Peru. It is associated with tetrahedrite, gustavite, barite, and pyrite. Terrywallaceite crystals are lath-shaped, metallic-black, with striations parallel to the elongated direction (the c axis). The mineral is opaque with black streak and metallic luster. It is brittle and has a Mohs hardness of ~4; cleavage is good on {010} and no parting was observed. Twinning is pervasive on (100). The calculated density is 6.005 g/cm 3 . Optically, terrywallaceite is grayish white in polished thin section, with weak bireflectance, weak pleochroism (white to pale gray), and weak anisotropy (gray with bluish tint to bluish black in air). An electron microprobe analysis yielded an empirical formula, based on 6 (S+As) apfu, Ag 1.02 Pb 0.87 (Sb 1.53 Bi 1.47 ) ∑=3.00 (S 5.94 As 0.06 ) ∑=6.00 . Terrywallaceite is a member of the lillianite group and isostructural with P 2 1 / c gustavite. Its unit-cell parameters are a = 6.9764(4), b = 19.3507(10), c = 8.3870(4) A, β = 107.519(2)°, and V = 1079.7(1) A 3 . The structure of terrywallaceite contains six symmetrically-nonequivalent S sites and five cation sites [Ag, Pb, M1 (=0.82Bi + 0.18Sb), M2 (=0.60Bi + 0.40Sb), and M3 (=0.95Sb + 0.05Bi)]. The pronounced preference of Sb for the M3 site over M2 and M1 in terrywallaceite is consistent with the site occupancy data reported for Sb-bearing gustavite, and suggests an alternative ideal formula for terrywallaceite of AgPb(Sb,Bi)(Bi,Sb) 2 S 6 , instead of AgPb(Sb,Bi) 3 S 6 .

Weissite from Gambatesa mine, Val Graveglia, Liguria, Italy: occurrence, composition and determination of the crystal structure

AbstractWeissite, Cu2–xTe (x ≈ 0.21), a very rare copper telluride, occurs in a sample from the Gambatesa mine, Val Graveglia, Liguria, Italy, where it occurs as purplish black anhedral grains up to 0.1 mm in length and shows a black streak. No cleavage is observed and the Vickers hardness (VHN100) is 142 kg/mm2. Weissite is dark bluish black, weakly pleochroic, and moderately anisotropic in bluish tints. Reflectance percentages in air for Rmin and Rmax are 37.0, 38.4 (471.1 nm), 33.2, 34.2 (548.3 nm), 31.2, 32.1 (586.6 nm), and 28.6, 31.0 (652.3 nm), respectively.Weissite is trigonal and belongs to the space group P3m1 with the following unit-cell parameters: a = 8.3124(7) Å, c = 21.546(1) Å, V = 1289.3(2) Å3, and Z = 24. Electron microprobe analyses gave the chemical formula (Cu1.62Ag0.04Au0.04Fe0.04Sb0.04)Σ=1.78(Te0.96S0.02Se0.02). The crystal structure has been solved and refined to R = 1.95%. It consists of Cu and Te polyhedra forming complex crystal-chemical environments as is typical of many intermetallic compounds. The exceedingly short bond distances observed among the metals are discussed in relation to other copper tellurides and pure metals.

Art in Science: Enhancing Observational Skills

Art in Science: Enhancing Observational Skills

GRP-112 Medical Devices in Morocco: What Guarantees of Quality and Safety?

BackgroundNowadays, all over the world, many medical devices, initially considered as non-risk or low risk, have been proved to be extremely dangerous to human health, as evidenced by the latest...

The Beat

The Beat

Plastics Color to commercialize its blue tint masterbatch

Colorant and additive masterbatch supplier Plastics Color Corp (PCC) is to begin marketing its SoluPLAs™ TN 920259 blue tint masterbatch. The company originally developed the product for NatureWorks for use in its Ingeo biopolymer. However, PCC will now market the masterbatch directly as a new grade within its SoluPLAs portfolio.

Raberite, Tl5Ag4As6SbS15, a new Tl-bearing sulfosalt from Lengenbach quarry, Binn valley, Switzerland: description and crystal structure

AbstractRaberite, ideally Tl5Ag4As6SbS15, is a new mineral from Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs very rarely as euhedral crystals up to 150 m m across associated with yellow needle-like smithite, realgar, hatchite and probable trechmannite, edenharterite, jentschite and two unidentified sulfosalts. Raberite is opaque with a metallic lustre and has a dark brown–red streak. It is brittle with a Vickers hardness (VHN10) of 52 kg mm–2 (range 50–55) corresponding to a Mohs hardness of 2½–3. In reflected light raberite is moderately bireflectant and very weakly pleochroic from light grey to a slightly greenish grey. It is very weakly anisotropic with greyish to light blue rotation tints between crossed polars. Internal reflections are absent. Reflectance percentages for the four COM wavelengths [listed as Rmin, Rmax, (λ)] are 30.6, 31.8 (471.1 nm), 28.1, 29.3 (548.3 nm), 27.1, 28.0 (586.6 nm), and 25.8, 26.9 (652.3 nm).Raberite is triclinic, space group P1, with a = 8.920(1), b = 9.429(1), c = 20.062(3) Å, α = 79.66(1), β = 88.84(1), γ = 62.72(1)º, V = 1471.6(4) Å3 and Z = 2. The crystal structure [R1 = 0.0827 for 2110 reflections with I > 2σ(I)] consists of columns of nine-coordinate Tl atoms forming irregular polyhedra extending along [001] and forming sheets parallel to (010). The columns are decorated by cornersharing MS3 pyramids (M = As, Sb) and linked by AgS3 triangles. Of the seven M positions, one is dominated by Sb and the others by As; the mean M-S bond distances reflect As ↔ Sb substitution at these sites.The eight strongest lines in the powder diffraction pattern [dcalc in Å (I) (hkl)] are: 3.580 (100) (13); 3.506 (58) (23); 3.281 (73) (006); 3.017 (54) (3); 3.001 (98) (133); 2.657 (51) (226); 2.636 (46) (300); 2.591 (57) (330). A mean of 9 electron microprobe analyses gave Tl 39.55(13), Ag 18.42(8), Cu 0.06(2), As 17.08(7), Sb 5.61(6), S 19.15(11); total 99.87 wt.%, which corresponds to Tl4.85Ag4.28Cu0.02As5.72Sb1.16S14.97 with 31 atoms per formula unit. The new mineral has been approved by the IMA-CNMNC Commission (IMA 2012-017) and is named for Thomas Raber, an expert on Lengenbach minerals.

Chovanite, Pb15-2xSb14+2xS36Ox (x ∼ 0.2), a new sulphosalt species from the Low Tatra Mountains, Western Carpathians, Slovakia

Chovanite, a new representative of the group of oxysulphosalts of Pb and Sb was found in three hydrothermal deposits of antimony ore, Dubrava, Male ´ ˇ Zelezne ´, and Klacianka, situated on the northern slopes of the Low Tatra Mountains, Slovakia. It is associated with other Pb-Sb sulphosalts, especially boulangerite, robinsonite and dadsonite. In reflected light, chovanite is white, bireflectance is distinct already in air. Pleochroism is present; colour varies from white with a yellowish green tint (darkest position) to white with a faint bluish tint (lightest position). Reflectance values in air are Rmax -R min (%) (l nm): 43.6-37.7 (470), 43.0-36.7 (546), 41.3-35.4 (589), 39.2-34.0 (650). Anisotropy is moderate to strong both in air and in oil, with blue grey to brown grey polarization colours. Internal reflections and twinning are absent. The optical properties are very similar to boulangerite. Micro-indentation hardness is 222.5 with a range 213-238. Derived Mohs hardness is 3. Cleavage is good, parallel to the c axis. Simplified chemical formula based on electron-microprobe analyses is Pb14.42(35)Sb14.33(11)S36.04(23), Z ¼ 4, which corresponds to Pb 50.74, Sb 29.63, S 19.62, total 100.00 wt%. No other elements exceed detection limits; chlorine is absent and oxygen was not measured. Structural formula is Pb15-2xSb14þ2xS36Ox (Z ¼ 4) for which the above mean of microprobe measurement data and the structure refinement give the value of x equal to � 0.2. Density (calc.) is 7.14 g/cm 3 . Crystal system is monoclinic, space group C2/m, lattice parameters a ¼ 48.189(48) A ˚ , b ¼ 4.1104(40) A ˚ , c ¼ 34.235(35) A ˚ , b ¼ 106.059(15) � , V ¼ 6517(11) A ˚ 3 , Z ¼ 4. Chovanite belongs to a sulphosalt family of boxwork structures, together with pellouxite, scainiite, pillaite, marruccite, vurroite, neyite, and several synthetic sulphosalts. Its crystal structure contains 11 independent lead sites, 13 coordination polyhedra of antimony, some of them with Sb sites split into two partially occupied non-overlapping positions, and five mixed Pb, Sb sites. The boxwork structure of chovanite is formed by a combination of three types of structural modules: (a) continuous walls with a complex structure of rod-layer type; these walls are interconnected by (b) rod-like partitions, and the resulting box-like channels (c) are filled by still another type of structure rods. Chovanite has the largest box-like channel system and infill elements known at present. In spite of differences in chemical composition, chovanite is structurally closest to pellouxite (Cu,Ag)2Pb21Sb23S55ClO which has a moderately large boxwork channel system.

Debattistiite, Ag9Hg0.5As6S12Te2, a new Te-bearing sulfosalt from Lengenbach quarry, Binn valley, Switzerland: description and crystal structure

AbstractDebattistiite, ideally Ag9Hg0.5As6S12Te2, is a new mineral (IMA-CNMNC 2011-098) from the Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs as very rare tabular euhedral crystals up to 150 μm across in cavities in dolomitic marble, associated with realgar, rutile, trechmannite and hutchinsonite. Debattistiite is opaque with a metallic lustre and a grey streak. It is brittle; the Vickers hardness (VHN25) is 80 kg mm–2 (range: 65–94), corresponding to a Mohs hardness of 2–2½. In reflected light debattistiite is dark grey, highly bireflectant and weakly pleochroic from dark grey to a slightly greenish grey. Between crossed polars it is highly anisotropic with brownish to blue rotation tints. Internal reflections are absent. Reflectance percentages for the four COM wavelengths (Rmin and Rmax) are 27.2, 34.5 (471.1 nm), 25.5, 31.0 (548.3 nm), 22.9, 28.4 (586.6 nm), and 20.1, 25.2 (652.3 nm), respectively.Debattistiite is triclinic, space group P1, with a = 7.832(5), b = 8.606(4), c = 10.755(5) Å, α = 95.563(9), β = 95.880(5), γ = 116.79(4)°, V = 635.3(6) Å3 and Z = 1. The crystal structure [R1 = 0.0826 for 795 reflections with I > 2σ(I)] consists of corner-sharing AsS3 pyramids forming three-membered distorted rings linked by Ag atoms in triangular or tetrahedral coordination.The five strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are as follows: 10.56 (6) (001); 3.301 (5) (12); 2.991 (4) (22); 2.742 (1) and 2.733 (10) (30). A mean of nine electron microprobe analyses gave: Ag 44.88, Hg 4.49, As 20.77, S 17.72, Te 11.82; total 99.68 wt.%, which corresponds to Ag9.02Hg0.49As6.012S11.98Te2.01, on the basis of 29.5 atoms. The new mineral is named for Luca De Battisti, a systematic mineralogist and expert on the minerals of Lengenbach quarry.

Review: Borromini’s Book: The “Full Relation of the Building” of the Roman Oratory by Francesco Borromini and Virgilio Spada of the Oratory by Kerry Downes

Kerry Downes. Borromini’s Book: The “Full Relation of the Building” of the Roman Oratory by Francesco Borromini and Virgilio Spada of the Oratory . Wetherby: Oblong Creative, 2009, 536 pp., 455 b/w and color illus. $99, ISBN 9780955657641 The nucleus of this weighty and ambitious book is an English translation of the Italian text of the Opus Architectonicum , a precious folio volume on the design and construction of the Oratorio dei Filippini, the oratory and conventual house of the Congregation of St. Philip Neri. This precocious “architectural monograph” was published in Rome in 1725 by Sebastiano Giannini, working from a manuscript (1644–47) composed by the Oratorian father Virgilio Spada in collaboration with his friend Borromini, who had been the architect of the Congregation for thirteen years (1637–50). A concise overview of the building’s history and importance, and a critical appreciation of Downes’s edition have been given recently by Joseph Connors.1 In many respects I cannot but second Connors’s more than adequate observations. Instead of adding similar remarks here, I should like to draw the reader’s attention to some different aspects of Downes’s opus. To start with the obvious: Downes’s book is eccentric and willfully anachronistic. The jacket photograph shows Borromini’s well-known facade in the slightly withered colors of a touristic slide from the 1960s. The image is repeated as Plate A, this time along with the adjacent facade of Santa Maria in Vallicella (the Chiesa Nuova) to show “mother and daughter” side by side. It imparts the atmosphere of a now-lost Rome, not only because of the sapling that has now grown to block half of the Oratory from sight, but also the tiny Fiat Cinquecento cars that once used to inhabit the piazza. Appearances are deceptive, however, for closer inspection reveals that the original photograph has been reworked with the help of “modern technology” (as Downes calls it, with an apparent mixture of respect and reservation): the verticals that a wide-angled lens at close range inevitably distorts have been straightened, and the pale morning sky …

CUPRONEYITE, Cu7Pb27Bi25S68, A NEW MINERAL SPECIES FROM BAITA BIHOR, ROMANIA

Cuproneyite, with an ideal formula Cu 7 Pb 27 Bi 25 S 68 , is a new mineral species found in the skarn deposit of Baiţa Bihor, Romania. The mineral occurs in irregular aggregates, nests and veinlets up to 5 cm across, with predominant cosalite, hammarite–friedrichite and calcite, within the diopside skarn. Cuproneyite is opaque, has a silver-grey color and a metallic luster, and it displays a perfect cleavage along crystal elongation. The average Mohs hardness is about 3, approximated from the average micro-identation hardness, 222.5 kg/mm 2 . Cuproneyite forms irregular or short prismatic grains up to 300 μm in length, intergrown with lamellae and irregular patches of cosalite and hammarite–friedrichite. Bireflectance is barely visible in air and moderate in oil immersion, with a greyish white color and faint yellowish tints in the lightest position, to greyish white with faint bluish tints in the darkest position. Between crossed polars, the rotation tints of the most anisotropic grains are dark brownish grey to light brownish grey. Internal reflections are absent. The reflectance data (measured in air; R min , R max ) are: 40.4, 47.1% at 470 nm, 39.3, 45.7% at 546 nm, 38.3, 44.3% at 589 nm, and 38.1, 43.9% at 650 nm. Twenty-four electron-microprobe analyses gave, as an average, Cu 3.34(12), Ag 0.30(3), Pb 40.10(27), Bi 39.59(18), Se 0.14(3), Te 0.12(4), S 16.12(7) wt%, corresponding to Cu 7.1 Ag 0.38 Pb 26.04 Bi 25.49 (Te 0.12 Se 0.23 S 67.65 ) ∑68 , calculated on the basis of (S + Se + Te) = 68 atoms per formula unit. The simplified formula [after reconversion of x (Ag + Bi) into 2 x Pb] is Cu 7 Pb 27 Bi 25 S 68 , in agreement with the empirical formula and the one deduced through crystal-structure analysis. Cuproneyite is monoclinic, space group C 2 /m , with a 37.432(8), b 4.0529(9), c 43.545(9) A, β 108.800(5)°, V = 6254(2) A 3 , Z = 2, with a calculated density of 7.11 g/cm 3 . The strongest lines in the calculated X-ray powder pattern [ d in A(I) hkl ] are: 3.735(96)1003, 3.507(50)316, 3.464(53)8011, 3.347(84)4010, 2.956(77)713, 2.925(46)8014, 2.867(100)714, and 2.027(81)020. Cuproneyite is structurally related to neyite, the main difference residing in the fact that the independent Ag position present in the neyite structure is completely replaced by Cu in cuproneyite.

Pseudolyonsite, Cu3(VO4)2, a new mineral species from the Tolbachik volcano, Kamchatka Peninsula, Russia

Pseudolyonsite, ideally Cu 3 (VO 4 ) 2 , is a new mineral from the medium-temperature fumaroles of the New Tolbachik scoria cones, Tolbachik volcano, Kamchatka Peninsula, Russia. It occurs as needles that are 5–20 μm across and up to 0.5 mm in the length, which sometimes produce parallel intergrowths, sprays or openwork clusters up to 2 mm. Associated minerals are: piypite, hematite, magnetite, lyonsite, aphthitalite, palmierite, langbeinite, filatovite, lammerite, vergasovaite, rutile and native gold. Pseudolyonsite is dark red with a brownish tint to black, translucent to opaque, with a reddish-brown streak and adamantine to semi-metallic lustre. The mineral is brittle, but thin long needles are flexible. The fracture is conchoidal, and no cleavage was observed. The calculated density is 4.749 g/cm 3 . In reflected light in air the mineral is grey with a weak bluish tint, non-pleochroic, has distinct anisotropy and ubiquitous red to orange internal reflections. The reflectance values (R 1 and R 2 , %) in air for the four COM wavelengths are, respectively, 17.05, 19.6 (470 nm); 16.1, 18.15 (546 nm); 15.85, 17.7 (589 nm); and 15.55, 17.4 (650 nm). Four electron probe (EDS) analyses produced the following mean values: V 2 O 5 40.37, CuO 48.83, ZnO 7.60, MoO 3 1.89, and SiO 2 0.14, total 98.83 wt%, which corresponds, on the basis of 8 O atoms, to (Cu 2.58 Zn 0.44 ) ∑3.02 (V 1.88 Mo 0.06 Si 0.02 ) ∑1.96 O 8 . The idealised formula is Cu 3 (VO 4 ) 2 . Pseudolyonsite is monoclinic: P 2 1 / c , a = 6.2695(4), b = 8.0195(3), c = 6.3620(3) A, β = 111.96(1)°, V = 296.66(3) A 3 , Z = 2. The strongest powder X-ray diffraction lines [ d in A (I) ( hkl )] are: 4.70 (60) (110); 3.30 (79) (021, 120); 3.22 (87) (111); 3.18 (34) (−121, −102); 2.894 (74) (200, −211); 2.761 (100) (012); 2.479 (59) (−212, −122); 2.419 (67) (031, 130). The crystal structure was solved from single-crystal data and refined to R = 0.0444. Pseudolyonsite is isostructural with synthetic monoclinic Cu 3 (VO 4 ) 2 . The crystal structure of pseudolyonsite contains corrugated octahedral layers formed by the chains of edge-shared, distorted Cu(2)-octahedra running along the c axis and connected to each other by distorted Cu(1)-octahedra. The octahedra of both types contain Cu and subordinate Zn, and they are typically Jahn-Teller-distorted. Adjacent octahedral layers are connected to each other by VO 4 tetrahedra. Pseudolyonsite is dimorphous with triclinic mcbirneyite. The name pseudolyonsite comes from its close visual similarity to another vanadate mineral, lyonsite, Cu 3 Fe 3+ 4 (VO 4 ) 6 . Both the mineral and its name have been approved by the IMA CNMNC (IMA No. 2009-062).

Advantages of Nano Pigments Over Micro Pigments in Obtaining Larger Spectra of Colours in CMYK System

Based on the CMYK colour system, it is possible to obtain the full colour spectrum with mixing the four colours – cyan, magenta, yellow and key (black). In this research, ceramic nano pigments including CoAl2O4 (cyan), Au (magenta), (Ti,Cr,Sb)O2 (yellow) and CoFe2O4 (key) were mixed together with different ratios and applied on glazed tiles and the colour specifications of the samples were measured. The Colours Software (CSA) was used for predicting the ratios of the pigments for obtaining a target or reference colour. For comparison, equivalent micro pigments, namely CoAl2O4, Cd(S,Se):ZrSiO4, (Ti,Cr,Sb)O2 and CoFe2O4 were also examined. It was observed that using the present nano pigments, it was possible to cover the fourth quarter of the CIELab circle close to a + axis, while this was not possible with the micro pigments. This was attributed to the blue tint present in Au nano pigment. It was also revealed that reaching the colours of grey, brown and beige shades was possible by both nano and micro sets of pigments, while making orange and yellow colours was difficult. Also, it was revealed that yellow nano and micro pigments did not have thermal stability at high temperatures. The results indicated that nano pigment with 4.592 < a * < 15.606 and −1.560 < b * < +1.549 had yellow and blue tints and its yellow tint was due to grain growth, but micro pigment showed more red and less yellow tint. The above mentioned a* and b* values indicate the high colour performance of the pigment.

&lt;I&gt;Peniophora pseudonuda&lt;/I&gt; is a synonym of &lt;I&gt;P. laeta&lt;/I&gt;

Abstract — Peniophora laeta is easily recognized because it is restricted to Carpinus as host in Europe, and the reddish yellow fruitbody is provided with prominent teeth or hyphal pegs, disrupting the bark when developing. P. pseudonuda was earlier not even thought of as related to P. laeta, because fruitbodies are smooth and developing on the bark. Moreover, fruitbody initiation starts with a thin layer of brown-pigmented hyphae on bark surface. This render a bluish tint to the mature fruitbody which is in striking contrast to the orange-yellow basidiomata found in P. laeta. Nevertheless, both ITS sequences and crossing tests show that P. pseudonuda is conspecific with P. laeta. This was confirmed also by similarity in spore, basidia and cystidia morphology.

What colour is a shadow?

What colour is a shadow? Black, grey, or some other colour? This article describes how touse a digital camera to test the hypothesis that a shadow under a clear blue sky has a bluetint. A white sheet of A4 paper was photographed in full sunlight and in shadowunder a clear blue sky. The images were analysed using a shareware programcalled ImageJ. The average red, green and blue pixel values in a region of interestdrawn on a photograph of the paper in sunlight and shadow were 0.3, 0.32, 0.38and 0.2, 0.3, 0.5 respectively, demonstrating that a shadow under a blue skyhas a blue tint. The experiment would be a useful exercise for a science class.

Two new species in Cortinarius subgenus Telamonia, Cortinarius brunneifolius and C. leiocastaneus, from Fennoscandia (Basidiomycota, Agaricales)

Two new Cortinarius species, C. brunneifolius and C. leiocastaneus, are described based on molecular and morphological data. Cortinarius brunneifolius looks like a trivial brown Telamonia. It is characterised by the fairly dark brown cap and gills contrasting with the white stem. The major distinctive features are the refracting, colourless granules in the epicutis hyphae, broadly ellipsoid, equally verrucose spores, and fruitbody without bluish tints. Cortinarius leiocastaneus can be fairly easily recognised by the appearance of miniature brown Telamonia species, narrowly amygdaloid spores, and a habitat with Betula. Detailed descriptions of the species are provided as well as comparisons with macro- and microscopically similar existing telamonioid taxa. Phylogenetic relationships within the genus were studied by use of ITS rDNA sequence data. Ten new ITS sequences are published. Cortinarius brunneifolius and C. leiocastaneus are fairly closely related and belong to the subgenus Telamonia sensu stricto. The infrasubgeneric relationships were not well resolved, but the new species seem to be unrelated to the macroscopically similar species and do not clearly belong to any of the existing sections.