American Mineralogist, Volume 93, pages 1686–1691, 2008 New Mineral Names* PAULA C. PIILONEN ,1,† GLENN POIRIER,1 AND KIMBERLY T. TAI T 2 1Mineral Sciences Division, Canadian Museum of Nature, P.O. Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada 2Department of Natural History, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada CALVER T I T E * Single-crystal X-ray studies of a grain removed from a pol- J.L. Jambor, A.C. Roberts, L.A. Groat, C.J. Stanley, A.J. Criddle, ished section indicate the mineral is cubic, with a = 5.337(1) with allowable space groups of Fm3m, F432, and F43m. A and M.N. Feinglos (2007) Calvertite, Cu5Ge0.5S4 , a new mineral species from Tsumeb, Namibia. Can. Mineral., 45, re-analysis a year later of the same single crystal produced no 1519–1523. reflections, but the original powder sample showed no change after 11 years. Calvertite was discovered during the examination of another The authors suggest that the small unit cell and the un- new mineral (gallobeaudanite) from the Tsumeb mine. The un- stable character of calvertite indicate that it is a metastable, oxidized portions of the sample in which calvertite was found highly disordered mineral whose ordered equivalent would consist mainly of calvertite and reinerite with minor tennantite be Cu10GeS8 with a = 2 × 5.337 Å. It is named for Lauriston and gallite inclusions. Calvertite occurs in a granular texture (Larry) Derwent Calvert (1924–1993) of the National Research formed by a network of chalcocite veins. The calvertite grains Council, Ottawa, Canada. Cotype polished sections of calver- are anhedral, elongate to elliptical with the largest grains up tite are in the Canadian Museum of Nature, Ottawa (CMNMC to 100 µm across. The calvertite postdates the reinerite as evi- 85731), and the Natural History Museum, London, U.K. (BM denced by veins of calvertite cutting reinerite. Other associated 2004, 78). G.P. minerals in the sample are goethite, hematite, quartz, Hg-rich CASSA G NAI T E * native silver, stolzite, otjisumerite, and various members of the alunite supergroup. R. Basso, C. Carbone, and A. Palenzona (2008) Cassagnaite, Calvertite has a metallic luster, irregular to conchoidal a new, V-bearing silicate mineral from the Cassagna mine, fracture, brittle tenacity, and no cleavage or parting. It is mac- northern Apennines, Italy. Eur. J. Mineral., 20, 95–100. roscopically black. The VHN is 283 kg/mm2 (Mohs hardness 4 to 5). It is opaque and pale bluish-gray in reflected light. No Cassagnaite is a new mineral found in the Val Graveglia birefringence, pleochroism, or internal reflections were observed. manganese district (Northern Apennines, Liguria, Italy) at the Reflectance percentages in air are 26.3 (470 nm), 23.1 (546), Cassagna mine. Cassaginaite was found in fractures in braunite + 22.2 (589), and 21.5% (650). quartz layered mineralization, together with piemontite. Hydro- Chemical composition was measured using an electron thermal fluid circulation, along later extensional fractures under microprobe. Weight percent results (and ranges in parentheses) decreasing P-T metamorphic conditions, induced the concentra- are as follows: Cu 63.10 (62.55–63.70), Fe 1.66 (1.49–1.84), tion of commonly dispersed elements that were involved into the Zn 0.55 (0.22–0.92), Ge 5.76 (5.58–5.98), As 1.50 (1.35–1.56), genesis of As-, Ba-, Cu-, Sr-, and V-rich mineral assemblages. Ga 0.36 (0.31–0.39), V 0.05 (0.04–0.05), S 26.63 (26.4–26.78), Vanadium minerals have been previously discovered at the two corresponding to an empirical formula (based of four S at- other mines in the area (Gambatesa and Molinello mines) such as cavoite, medaite, palenzonaite, reppiaite, saneroite, tiragalloite, oms per formula unit) of (Cu4.782Fe0.143Zn0.041Ga0.025V0.005)Σ4.996 3 vanadiocarpholite, and vanadomalayaite, this is the first time a (Ge0.382As0.096)Σ0.478S4, Z = 1, Dcalc = 5.239 g/cm . The powder diffraction pattern for calvertite consists of only newly described vanadium mineral was discovered at this mine. four lines: [d in Å (I%,hkl)]: 3.053(100,111), 2.639(10,200), Cassagnaite appears as very rare isolated prismatic to tabular 1.869(90,220), and 1.595(30,311). These lines do not definitively {001} crystals, usually elongated along [100], and as entangled aggregates of a few crystals. The crystals are generally very identify the mineral. The X-ray pattern of synthetic Cu3GeS4 also consists only of four lines, all of which moderately match those small, with a maximum size of 0.06 mm. of calvertite. The strongest lines of reinerite, germanocolusite, Cassagnaite is transparent with vitreous luster, golden brown and germanite also agree well with those of calvertite. in color, and the streak is nearly white. The morphology of the crystals is generally dominated by the prism {011} and the pina- coids {001} and {100}. It is brittle and exhibits {001} cleavage * Before publication, minerals marked with an asterisk were (or parting). Due to the unusual scarcity of available material and approved by the Commission on New Minerals and Mineral to the reduced size of the crystals, the determinations of physical Names, International Mineralogical Association. and optical properties are not complete. The calculated density is † E-mail: [email protected] 3.22 g/cm3. The mineral does not fluoresce under short and long- 0003-004X/08/0010–1686$05.00/DOI: 10.2138/am.2008.527 1686 NEW MINERAL NAMES 1687 wave ultraviolet light. Optically, cassagnaite is biaxial and some district, Ryazan’ Oblast, 350 km east-south of Moscow, Russia optical measurements were performed on the largest face, likely (54°44.8' N; 41°25.3' E). parallel to the {001} cleavage, of a prismatic crystal elongated Chukanovite is monoclinic P21/a, with a = 12.396(1) Å, b = along [100]. The refractive index values are N (parallel to a): 9.407(1) Å, c = 3.2152(3) Å, β = 97.78° and closely related to 1.810 (±0.005) and n: 1.800 (±0.005), measured by Cargille’s the minerals of the malachite-rosasite group. The strongest lines liquids at 25 °C (λ = 589 nm). The pleochroism is very weak: N of the X-ray powder pattern [d in Å (I%,hkl)] are: 6.14(40,200), = golden yellow-brown and n = pale golden yellow-brown. 5.15(60,231), 3.73(80,310), 2.645(100,230), 2.361(40,510), The crystal structure, refined in the space group Cmcm 2.171(40,520). The structure of chukanovite was refined on with unit-cell parameters a = 6.066(1) Å, b = 8.908(1) Å, c = synchrotron data by the Rietveld method up to Rp = 3.43%, wRp 18.995(2) Å, and Z = 2, may be described as a layer stacking = 4.51%, and RBragg = 2.48%. along [001] of a fundamental building block of composition Unaltered chukanovite is transparent, pale-green, or colorless. 4− [M12(OH)2(SiO4)2] that alternates with intersheets, randomly The surface of aggregates is brownish-green. Streak is white, 2+ 4+ – occurring in a ratio ideally 1:1, of type 1 [(Ca, Mn )2SiO2] luster is vitreous, cleavage is perfect, probably on {021}, and 2+ 4+ 3+ 3+ and of type 2 (Ca,Mn )2M22(OH)2O2] , where Fe and Mn the fracture is uneven. The mineral is brittle, the Mohs hardness populate 3/4 of the M1 site and Al the remaining 1/4, while is 3.5–4, and the calculated density is 3.60 g/cm3. It is optically 3+ V , Mg, and Al occupy in nearly equal proportions the M2 site. biaxial (–) with α = 1.673(3), β = 1.770(5), γ = 1.780(5), 2Vmeas All the checked crystals exhibit very poor reflection quality, = 10(5)°. Chukanovite occurs as acicular to fibrous individuals, almost all exhibited a large quantity of streaked reflections, elongated along [001], up to 0.5 mm long and up to 2–3 μm likely related to a high degree of structural disorder, and thick usually combined in spherulites up to 0.3 mm (rarely up generally weak reflections likely due to the small size. The to 1 mm) in diameter. Botryoidal spherulitic clusters and paral- proposed structure of cassagnaite represents at present an lel- or radial-columnar aggregates forming crusts up to 1 mm averaged model of a high disordered structure and attempts thick are typical. Aggregates are usually porous; the core of will be made to improve it. some spherulites contains grains of kamacite, taenite, sulfides, Quantitative analyses (seven points on two crystals) were or iron hydroxides. performed by means of an electron microprobe (PHILIPS The infrared spectrum of the new mineral is close to the spec- SEM 515 electron microscope equipped with EDAXPV9100 tra of pokrovskite (the most similar), malachite, and members spectrometer) in energy-dispersion mode, with an accelerat- of the rosasite group. Absorption bands in the IR spectrum of −1 ing voltage of 15 kV and a beam current of about 2 nA. H2O chukanovite (in cm ; frequencies of the most intensive bands are content could not be directly determined because of the lack of italic, sh = shoulder) are: 3475, 3325, 1755, 1521, 1400sh, 1364, material but a micro-Raman analysis has been carried out with 1069, 1055sh, 955, 861, 837, 781, 710sh, 695, 655, 504, 452. a Renishaw 2000 Ramascope equipment using a laser operating Average chemical composition (wt%; electron probe, H2O by −1 at 633 nm; the large band in the range 3500–3000 cm of the modified Penfield method, CO2 by selective sorption) is MgO − Raman shift shows the presence of (OH) ions in the structure of 0.1, FeO 68.8, NiO 0.6, CO2 19.8, H2O 10.9, total 100.2 wt%.