Publication Type:

Book Chapter

Authors:

McDonald, Andrew M.; Cabri, Louis J.; Stanley, Chris J.; Good, David J.; Redpath, Jason; Lane, Geoff; Spratt, John; D. Ames

Source:

A tribute to John Leslie Jambor, Mineralogical Association of Canada, Ottawa, ON, Canada, Volume 53, p.845-857 (2015)

ISBN:

0008-4476

Keywords:

arsenides, bismuthides, Canada, chemical composition, coexisting minerals, coldwell complex, crystal chemistry, crystal structure, eastern canada, electron probe data, formula, lattice parameters, metals, michenerite, new minerals, Ontario, optical properties, Palladium, platinum group, platinum minerals, reflectance, silver, space groups, sperrylite, sulfides, unit cell, x-ray diffraction data

Abstract:

Coldwellite, ideally Pd (sub 3) Ag (sub 2) S, is a new mineral species discovered in a heavy-mineral concentrate from the Marathon deposit, Coldwell Complex, Ontario Canada. It is cubic, crystallizing in space group P4 (sub 3) 32 (#212) with a 7.2470(8) A, V 380.61(1) A (super 3) , Z = 4. The five strongest lines of the X-ray powder-diffraction pattern [d in A (I)(hkl)] are: 2.427(100)(221), 2.302(38)(310), 2.195(38)(311), 1.4280(44)(510,431), 0.9294(24)(650,643), and 0.9208(20)(732,651). Associated minerals in the discovery sample include Au-Ag alloy, hollingworthite, isoferroplatinum, keithconnite, kotulskite, mertieite-II, michenerite, palladoarsenide, sobolevskite, sperrylite, stillwaterite, vysotskite, Ti- and Cr-rich magnetite and ilmenite, pyrrhotite, chalcopyrite, and pentlandite, with trace amounts of bornite, cobaltite, and galena. Coldwellite is white with a light pinkish brown tint, and it has a metallic luster. No streak or microhardness could be measured. The mineral shows no internal reflections, pleochroism, bireflectance, or anisotropy. The reflectance values (%) in air for the standard COM wavelengths are: 41.9 (470 nm), 44.9 (546 nm), 44.0 (589 nm), and 45.0 (650 nm). The density, 9.90(1) g/cm (super 3) , was calculated using the empirical formula and the unit-cell parameters from the refined crystal-structure. The average result (n = 23) of electron-microprobe analyses is: Pd 56.1, Fe 0.16, Ag 38.2, S 5.63, total 100.09 wt.%, which corresponds to (Pd (sub 2.99) Fe (sub 0.02) ) (sub Sigma 3.01) Ag (sub 2.00) S (sub 0.99) , based on 6 apfu The name recalls the type locality.

Notes:

GeoRef, Copyright 2018, American Geological Institute.<br/>2016-094380<br/>coldwellite<br/>hollingworthite<br/>isoferroplatinum<br/>keithconnite<br/>kotulskite<br/>Marathon Deposit<br/>mertieite<br/>palladoarsenide<br/>sobolevskite<br/>stillwaterite<br/>vysotskite