Abstract
Bottinoite, a new nickel and antimony hydrated hydroxide mineral, occurs at the Bottino mine, Alpi Apuane, Italy. Associated minerals are ullmannite, siderite, calcite, quartz, phlogopite, pyrite, chalcopyrite, and an unidentified species containing Sb, Ni, and As. The mineral occurs as tabular or very short prismatic crystals with prominent {0001} forming roselike aggregates; crystals up to 0.4 mm and aggregates up to 2.5 mm in diameter. The mineral is light blue-green, transparent, nonfluorescent, with a vitreous luster and a very light blue streak. It is brittle, with conchoidal fracture. VHN10 = 105 kg/mm2. Dcalc = 2.81 g/cm3, Dmeas = 2.83(1), determined for synthetic crystals by heavy liquids. Bottinoite is uniaxial (+), nonpleochroic, with ω = 1.600(10), ∈ = 1.605(10), and very low birefringence. It is trigonal, a = 16.026(3), c = 9.795(2) Å, V = 2178.6(7) Å3, c/a = 0.6112, Z = 6, space group choices are P31m or, more likely, P31m or P312. The strongest six lines in the X-ray powder diffraction pattern (dobs, Iobs, hkl) are 4.62(100)300, 3.36(100)032, 2.34(80)332, 2.09(60)062, 1.806(70)334, 1.751(60)360. On the basis of chemical analysis, IR spectroscopy, TGA, and X-ray data, bottinoite corresponds to the synthetic compound Ni(H2O)6[Sb(OH)6]2. The mineral is named for the Bottino mine, which is the type locality.
