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Menezesite, ideally Ba2MgZr4(BaNb12O42)·12H2O, occurs as a vug mineral in the contact zone between dolomite carbonatite and "jacupirangite" (=a pyroxenite) at the Jacupiranga mine, in Cajati county, São Paulo state, Brazil, associated with dolomite, calcite, magnetite, clinohumite, phlogopite, ancylite-(Ce), strontianite, pyrite, and tochilinite. This is also the type locality for quintinite-2H. The mineral forms rhombododecahedra up to 1 mm, isolated or in aggregates. Menezesite is transparent and displays a vitreous luster; it is reddish brown with a white streak. It is non-fluorescent. Mohs hardness is about 4. Calculated density derived from the empirical formula is 4.181 g/cm³. It is isotropic, nmeas > 1.93(1) (white light); ncalc = 2.034. Menezesite exhibits weak anomalous birefringence. The empirical formula is (Ba1.47K0.53Ca0.31Ce0.17Nd0.10Na0.06La0.02)Σ2.66(Mg0.94Mn0. 23Fe0.23Al0.03)Σ1.43(Zr2.75Ti0.96Th0.29)Σ4.00 [(Ba0.72Th0.26U0.02)Σ1.00(Nb9.23Ti2.29Ta0.36Si0.12)Σ12.00O42]·12H2O. The mineral is cubic, space group Im0̄３ (204), a = 13.017(1) Å, V = 2206(1) ų, Z = 2. Menezesite is isostructural with the synthetic compound Mg7[MgW12O42](OH)4·8H2O. The mineral was named in honor of Luiz Alberto Dias Menezes Filho (born 1950), mining engineer, mineral collector and merchant. Both the description and the name were approved by the CNMMN-IMA (Nomenclature Proposal 2005-023). Menezesite is the first natural heteropolyniobate. Heteropolyanions have been employed in a range of applications that include virus-binding inorganic drugs (including the AIDs virus), homogeneous and heterogeneous catalysts, electro-optic and electrochromic materials, metal and protein binding, and as building blocks for nanostructuring of materials. [ABSTRACT FROM AUTHOR]

A new occurrence of rankamaite is here described at the Urubu pegmatite, Itinga municipality, Minas Gerais, Brazil. The mineral forms cream-white botryoidal aggregates of acicular to fibrous crystals, intimately associated with simpsonite, thoreaulite, cassiterite, quartz, elbaite, albite, and muscovite. The average of six chemical analyses obtained by electron microprobe is (range in parentheses, wt%): Na2O 2.08 (1.95-2.13), K2O 2.61 (2.52-2.74), Al2O3 1.96 (1.89-2.00), Fe2O3 0.01 (0.00-0.03), TiO2 0.02 (0.00-0.06), Ta2O5 81.04 (79.12-85.18), Nb2O5 9.49 (8.58-9.86), total 97.21 (95.95-101.50). The chemical formula derived from this analysis is (Na1.55K1.28)σ2.83(Ta8.45Nb1.64Al0.89Fe0.013+Ti0.01)σ11.00[O25.02(OH)5.98]σ31.00. Rankamaite is an orthorhombic "tungsten bronze" (OTB), crystallizing in the space group Cmmm. Its unit-cell parameters refined from X-ray diffraction powder data are: a = 17.224(3), b = 17.687(3), c = 3.9361(7) Å, V = 1199.1(3) ų, Z = 2. Rietveld refinement of the powder data was undertaken using the structure of LaTa5O14 as a starting model for the rankamaite structure. The structural formula obtained with the Rietveld analyses is: (Na2.21K1.26)σ3.37(Ta9.12Nb1.30 Al0.59)σ11.00[O26.29(OH)4.71]σ31.00. The tantalum atoms are coordinated by six and seven oxygen atoms in the form of distorted TaO6 octahedra and TaO7 pentagonal bipyramids, respectively. Every pentagonal bipyramid shares edges with four octahedra, thus forming Ta5O14 units. The potassium atom is in an 11-fold coordination, whereas one sodium atom is in a 10-fold and the other is in a 12-fold coordination. Raman and infrared spectroscopy were used to investigate the room-temperature spectra of rankamaite. [ABSTRACT FROM AUTHOR]

Matioliite, ideally NaMgAl5(PO4)4 (OH) 6·2H2O, occurs as a secondary hydrothermal mineral in the Gentil mine granite pegmatite, Mendes Pimentel Co., Minas Gerais, Brazil. Some crystals are zoned to more Fe-rich compositions with an Fe2+:Mg ratio of approximately 1:1, corresponding to an intermediate member of the burangaite-matioliite solid-solution series. Matioliite is intimately associated with fluorapatite, crandallite, and zoned gormanite-souzalite cystals. The mineral forms prismatic to tabular crystals, up to 1 mm long. Matioliite is transparent and displays a vitreous luster; it is blue to colorless with a white streak. It is non-fluorescent. Mohs hardness is about 5. Calculated density is 2.948 g/cm³. Matioliite is biaxial negative, ηα = 1.597(2), ηβ = 1.627(2), ηγ = 1.632(1) (white light), 2V (meas.) = 43(2)°, 2V (calc.) = 44°, dispersion r > v, orientation X = b, Z ∧ c = 6°. Pleochroism is Y > X > Z, X = light blue to colorless, Y = blue, Z = colorless. The empirical formula is (Na0.94Ca0.01)∑0.95 (Mg0.88Fe0.112+Mn0.01)∑1.00(Al4.84Fe0.133+)∑4.97 (PO4)4.03(OH)5.76·2H2O. The mineral is monoclinic, space group C2/c, a = 25.075(1) Å, b = 5.0470(3) Å, c = 13.4370(7) Å, β = 110.97(3)°, V = 1587.9(4) ų, Z = 4. Crystal-structure determination was carried out and showed it is isostructural with burangaite, dufrénite, and natrodufrénite. Both the description and the name were approved by the CNMMN-IMA (Nomenclature Proposal 2005-011). The "magnesium analog of burangaite" described from the Gold Quarry mine, Carlin-trend, Eureka County, Nevada; "burangaite" from Hochgosch, Millstätter See-Rücken, Kärnten, Austria; and "burangaite" described from Córrego Pomarolli, Linópolis, Divino das Laranjeiras, Minas Gerais, Brazil, are probably matioliite. [ABSTRACT FROM AUTHOR]

Many plants are used in traditional medicine as active agents against various effects induced by snakebite. Few attempts have been made however to identify the nature of plant natural products with anti-ophidian properties. Baccharis trimera (Less) DC (Asteraceae), known in Brazil as carqueja, has been popularly used to treat liver diseases, rheumatism, diabetes, as well as digestive, hepatic and renal disorders. The active component was identified as 7alpha-hydroxy-3,13-clerodadiene-16,15:18,19-diolide, C20H28O5, (clerodane diterpenoid, Bt-CD). We report now the anti-proteolytic and anti-hemorrhagic properties against snake venoms of a Bt-CD inhibitor from B. trimera. Bt-CD exhibited full inhibition of hemorrhage and proteolytic activity caused by Bothrops snake venoms. The inhibitor was able to neutralize the hemorrhagic, fibrinogenolytic and caseinolytic activities of class P-I and III metalloproteases isolated from B. neuwiedi and B. jararacussu venoms. No inhibition of the coagulant activity was observed. Bt-CD also partially inhibited the edema induced by other crude venoms, metalloproteases, basic and acidic phospholipases A2. To further elucidate the inhibitory specificity of Bt-CD against metalloproteases isolated from snake venoms, a deeper understanding of its structure and function is necessary. Furthermore, the potential use of these inhibitors to complement anti-venom as an alternative treatment of snakebite envenomations needs to be evaluated in future studies.