Sodium scandium diphosphate, NaScP2O7, isotypic with α-NaTi(III)P2O7

Crystals of the title compound, NaScP2O7, were grown by a flux method. The crystal structure is isotypic with those of α-NaTiP2O7, NaYbP2O7 and NaLuP2O7, and is closely related to that of NaYP2O7. The structural set-up consists of a three-dimensional framework of P2O7 units that are corner-shared by ScO6 octa­hedra, forming tunnels running parallel to [010]. The Na atoms are situated in the tunnels and are surrounded by nine O atoms in a distorted environment

NEOBVYKLÁ SN-MINERALIZACE Z NYF PEGMATITU U KLUČOVA; TŘEBÍČSKÝ MASIV, MOLDANUBIKUM

Sn-mineralisation was found in the NYF pegmatite near Klučov, in the Třebíč Massif. It fills small veinlets in albitized graphic or blocky K-feldspar zone. Two different mineral assemblages were distinguished: herzenbergite-varlamoffite-stokesite-cassiterite and cassiterite-varlamoffite-tinzenite. Lathy herzenbergite I crystals up to 2 mm were formed during primary crystallization from late hydrothermal fluids and their chemical composition correspond to SnS with small amount of Cu and Fe. Varlamoffite and stokesite form fine grained aggregates and their textural relationships suggest replacement of herzenbergite

Giftgrubeite, CaMn2Ca2(AsO4)2(AsO3OH)2·4H2O, a new member of the hureaulite group from Sainte-Marie-aux-Mines, Haut-Rhin Department, Vosges, France

Giftgrubeite, ideally CaMn2Ca2(AsO4)2(AsO3OH)2·4H2O, is a new mineral occurring at the Giftgrube Mine, St Jacques vein, Rauenthal, Sainte-Marie-aux-Mines, Haut-Rhin Department, Grand Est, France and named after the type-locality. Giftgrubeite is mostly associated with Mn-bearing calcite, native arsenic, löllingite, and picropharmacolite. It is a recent secondary mineral, formed by alteration of the arsenical vein minerals after mining. Giftgrubeite occurs in colorless, rarely pearl white to pale yellow rosettes of brittle tabular crystals flattened on {1 0 0} and up to 0.2 mm in size. Hardness (Mohs) is 3 ½, Dmeas is 3.23(2) g·cm-3, Dcalc is 3.24 g·cm-3. The new mineral is biaxial negative without pleochroism. Measured 2V angle is ~72° and calculated 2V angle is 75.1°; the refractive indices measured in white light are: α = 1.630(2), β= 1.640(2) and γ = 1.646(2). The most prominent Raman bands are at 902, 885, 864, 851, 824, 797 and 759 cm-1. The empirical chemical formula is (Ca3.04Mn1.30Mg0.38Fe0.28)Σ5.00(AsO4)1.99(AsO3OH)2·4H2O. Giftgrubeite is monoclinic, C2/c, Z = 4, with a = 18.495(7) Å, b = 9.475(4) Å, c = 9.986(4) Å, β = 96.79(3)° and V = 1737.7(12) Å3. The six strongest lines in the X-ray powder diffraction pattern are [d in Å (I)(hkl)]: 3.33 (100)(-2 2 2), 3.18 (80)(2 2 2), 2.414 (60)(7 1 1), 4.80 (50)(-3 1 1), 4.65 (50)(-2 0 2) and 3.05 (50)(1 1 3). The structure of giftgrubeite was solved from the crystal retrieved from the type specimen by the charge-flipping algorithm. Giftgrubeite contains a well-known structure type parent to the hureaulite group of minerals, which is based upon an octahedral edge-sharing pentamers of M2+-polyhedra; pentamers linked into a loose framework by sharing corners with octahedra in adjacent pentamers and further by AsO4 and AsO3OH tetrahedra. There are three distinct octahedral sites: M1, M2, and M3. In the case of giftgrubeite, two of the M sites were found to be fully occupied by Ca; namely M1 and M3. The M2 site was then found to contain Mg besides dominant Mn. Considering the refined site occupancies, the structural formula for giftgrubeite is Ca3Mn1.30Mg0.70(AsO4)2(AsO3OH)2(H2O)4. Giftgrubeite is an ordered intermediate member between villyaellenite, MnMn2Ca2(AsO3OH)2(AsO4)2·4H2O and sainfeldite, CaCa2Ca2(AsO4)2(AsO3OH)2·4H2O

O kutání a rudách v Janově u Jindřichova ve SlezskU

The town Janov in Jeseníky Mts (near of Zlaté Hory) acquired mining law in the 16th century. The locations of mines were unknown. The ore (arsenopyrite in quartz matrix) was found only in 1961. The mineralogical and chemical characteristic suggest the metamorphogenic secretion origin of the mineralization

PRACOVIŠTĚ ELEKTRONOVÉ MIKROSKOPIE A MIKROANALÝZY: VYTVÁŘENÍ SPOLEČNÝCH PRACOVIŠŤ – CESTA K INTEGRACI VÝZKUMU, VÝUKY A PRAXE

The article describes the analytical capabilities of a new microanalytical facility, established jointly by the Masaryk University in Brno and the Czech Geological Service. The core instrument of the Centre of Electron Microscopy and Microanalysis is an electron microprobe CAMECA SX100, equipped with 5 WD spectrometers (two of them with large LIF and PET crystals, three with layered crystals for light element analysis), an ED analysis system PGT, SE, BSE detectors, CL camera, and a built-in optical polarizing microscope)

Position evaluation of ex-core neutron flux measurement in new type graphite reactors

Several concepts of new reactors use graphite. Some of them use graphite as a moderator, some of them as a reflector. There are at least two concepts of these graphite-type reactors under development in the Czech Republic. Both reactors use graphite as the reflector. An in-core measurement might be impossible to use because of various reasons, for instance, high temperature or aggressive environment. Therefore, this article focuses on ex-core neutron flux measurement system placed in the graphite reflector and the optimization of ex-core detector position. A set of experiments were performed at LR-0 reactor. The LR-0 is a light water reactor with a well-defined neutron field, which can be used for different material insertion tests and testing of its influence on criticality. Several modifications of LR-0 cores were modelled in Monte Carlo codes Serpent and KENO. A set of calculations were performed for verification of the criticality and neutron flux course in the reactor core and graphite reflector. Further investigation was focused on the influence of the presence of a graphite reflector on the neutron distribution in the reactor core. The LR-0 graphite experiments were also used to verify the calculations. Based on the results of this article, the optimal position of ex-core detectors in the graphite reflector is proposed

ZPRÁVA O VÝZKUMU SN-BOHATÉ MINERÁLNÍ ASOCIACE S AS-VESUVIANEM V NEDVĚDICKÉM MRAMORU U KOZLOVA NA ZÁPADNÍ MORAVĚ, SVRATECKÉ KRYSTALINIKUM

Insignificant skarn-like rock was discovered in Nedvědice marble near Kozlov (near Štěpánov nad Svratkou, Svratka Crystalline Complex). It contains distinctive Sn-, As- rich mineral assemblage comprising largely green Sn-bearing andradite with sporadic grossularite relics, As-bearing vesuvianite, malayaite and also As-bearing fluorapatite, nordenskiöldine and cassiterite as accessories. Two main stages of development of the mineral assemblage were distinguished. The first, relatively HT stages, producing tin-bearing andradite (1.2–2.4 wt. % SnO2), malayaite and arsenic-bearing vesuvianite (≤1.97 wt. % As2O5). In the retrograde alteration stage stokesite, „hydrocassiterite“ and unidentifi ed Ca-Fe-arsenates replaced of minerals of the first stage. Primary iron-rich assemblage crystallised under oxidic conditions especially enriched in Sn, As and B, highly various in Si activity and CO2 fugacity