Pyrite, arsenopyrite, sphalerite, marcasite, wolframite and rutile. Mount Pleasant, New Brunswick, Canada

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Subhedral rhombs of arsenopyrite (white, centre, bottom) have higher reflectance than pyrite (pale yellow, top left). Pyrite forms coarse-grained crystals (top left) but much of it is finely intergrown with marcasite (blue-yellow, slightly higher reflectance, right bottom). Sphalerite (medium grey, bottom left) contains abundant fine-grained and submicroscopic chalcopyrite inclusions which give the sphalerite a yellow-brown colour, especially in the cores of the crystals. A single tabular crystal of wolframite (brown-grey, bottom centre) is present. Rutile (light grey, top centre) forms anhedral aggregates and acicular crystals.

Polished block, plane polarized light, x 80, air

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