Ben Schumer's Photo Gallery
1HF-WVMCylindrite Pb3Sn4FeSb2S14 , Sphalerite ZnS , Quartz SiO2
Poop贸, Poop贸 Province, Oruro, BoliviaField of View: 0.8 mm
Vivid anisotropy of cylindrite in brownish, orange, and gray tones. Brown and colorless internal reflections are sphalerite-wurtzite and quartz, respectively.
Polished section, crossed polarizers (air). Field is 0.8 mm wide. Ben Schumer collection and photo.
EQ6-ME3K毛sterite Cu2ZnSnS4 , Cylindrite Pb3Sn4FeSb2S14 , Sphalerite ZnS
Poop贸, Poop贸 Province, Oruro, BoliviaField of View: 0.8 mm
Orange-brown k毛sterite aggregates on and in creamy cylindrite, all in massive dark-gray sphalerite-wurtzite. Traces of bright, creamy white franckeite and an unknown bluish-gray mineral, possibly galena, are visible in the large k毛sterite aggregate. The large cylindrite is cut oblique to the axis of elongation, showing an oval cross-section, and tiny cylindrite crystals in the sphalerite-wurtzite show their true triclinic morphology.
Polished section, plane polarized light (air). Field is 0.8 mm wide. Ben Schumer collection and photo.
PD5-03VCylindrite Pb3Sn4FeSb2S14 , Sphalerite ZnS
Poop贸, Poop贸 Province, Oruro, BoliviaField of View: 0.8 mm
Cylindrite, medium gray, in dark gray massive sphalerite-wurtzite from Poop贸, Bolivia. The cylindrite is cut perpendicular to the axis of elongation, showing how this hollow cylinder is formed from a single curved, sheetlike crystal. Filigree crystals in voids are either cylindrite or franckeite sheets. Daughter photo shows the same field with crossed polarizers.
Plane polarized light (air). Field is 0.8 mm wide. Ben Schumer collection and photo.
2P4-0W8Mawsonite Cu6Fe2SnS8 , Colusite Cu13VAs3S16 , Bornite Cu5FeS4 , Pyrite FeS2
Butte Mining District, Silver Bow County, Montana, USAField of View: 0.32 mm
Photomicrograph showing accessory sulfides in massive bornite ore from Butte. Tiny grains of mawsonite (mw) exhibiting reflection pleochroism in brownish to orange tones is associated with buff-colored colusite (col). Both minerals are hosted in bornite (bn); pyrite (py) hosts inclusions of colusite surrounded by thin rims of bornite. Scattered light gray grains of chalcocite are also present in the bornite.
Polished section, plane polarized light, FOV = 0.32 mm. Ben Schumer collection and photo.
KK9-1L6Digenite Cu9S5 , Chalcocite Cu2S , Covellite CuS , Bornite Cu5FeS4
Bisbee, Cochise County, Arizona, USAField of View: 0.8 mm
Photomicrograph of hypogene copper sulfides from Bisbee. Bluish-gray digenite (dg) is surrounded by gray chalcocite (cc) and brilliantly bireflectant and pleochroic blue covellite (cv), with scattered reddish grains of bornite (bn). Gangue is dark gray. No mine attribution was supplied with this sample but the paragenesis is nearly identical to massive sulfides mined from the 39-A stope, 1300 level of the Cole mine.
Polished section, plane polarized light, FOV = 0.8 mm. Ben Schumer collection and photo.
V77-D9YDigenite Cu9S5 , Pyrite FeS2 , Sphalerite ZnS , Tennantite Subgroup Cu6(Cu4C2+2)As4S12S
Bisbee, Cochise County, Arizona, USAField of View: 0.8 mm
Photomicrograph of hypogene massive sulfide ore from Bisbee. This ore is composed predominantly of digenite (dg) associated with pyrite (py), sphalerite (sph), and minor tennantite (tn) in a gangue of quartz and kaolinite/dickite (dark). Minor intense blue covellite is also present. No mine name was given with the specimen, but this material is almost identical to steely chalcocite-digenite ore from the 1300 level, 39-A stope in the Cole mine (actually closer to the Dallas shaft than the Cole).
Polished section, plane polarized light, FOV = 0.8 mm. Ben Schumer collection and photo.
4V5-Q1AMawsonite Cu6Fe2SnS8 , Bornite Cu5FeS4 , Chalcopyrite CuFeS2
Magma Mine, Superior, Pinal County, Arizona, USAField of View: 0.32 mm
Mawsonite (mw) exhibiting reflection pleochroism in orange to brown shades. The mawsonite is hosted in reddish brown bornite (bn) which also contains scattered yellow chalcopyrite (cpy) grains. This section is made from a chunk of massive bornite cut by a sheet of native silver <1 mm thick, mined from from a stope just below the 3600 level on the Koerner vein.
Polished section, plane polarized light (air), FOV = 0.32 mm. Ben Schumer collection and photo.
AFA-E5PPetzite Ag3AuTe2 , Hessite Ag2Te , Rucklidgeite PbBi2Te4 , Altaite PbTe , Pyrite FeS2
Campbell Mine, Bisbee, Cochise County, Arizona, USAField of View: 0.8 mm
Tellurides filling the interstices of compact pyrite (py) mass from the silica-pyrite core of the Campbell orebody. Petzite (p) occurs as massive, gray with a purple tinge material, and contains complex inclusions of intergrown brownish-gray, pleochroic hessite (h), pinkish laths of rucklidgeite (r), and white altaite (a). Carbonate, quartz, and mica gangue is very dark gray to black.
Petzite was identified by its color and perfect cubic cleavage, all other minerals were identified by optical properties. Plane polarized light (air), FOV = 0.8 mm. Ben Schumer collection and photo.
VQ7-3K8Volynskite AgBiTe2 , Rucklidgeite PbBi2Te4 , Hessite Ag2Te , Altaite PbTe , Pyrite FeS2
Campbell Mine, Bisbee, Cochise County, Arizona, USAField of View: 0.32 mm
Interstices of pyrite crystals (py) filled by a complex association of tellurides from the silica-pyrite core of the Campbell orebody. Over 14 different telluride species have been identified in ores from the Campbell mine at Bisbee, often in complex intergrowths. This sample contains six different tellurides, only four of which are visible here: rounded grains of pale lilac-gray volynskite (v) associated with pinkish laths of rucklidgeite (r) in gray hessite (h; weak reflection pleochrosim visible) with an alteration rim of white altaite (a) and oxidation products. Minor yellow chalcopyrite is also in association. All minerals were identified by optical properties.
Polished section, plane polarized light (air), FOV = 0.32 mm. Ben Schumer collection and photo.
0A9-080Pyrargyrite Ag3SbS3 , Galena PbS , Arsenopyrite FeAsS
Ojuela Mine, Mapim铆, Mapim铆 Municipality, Durango, MexicoField of View: 0.32 mm
Bluish-gray pyrargyrite (pyr) occurs as inclusions in galena (gn) associated with arsenopyrite (apy) in this sample from the Ojuela mine. It was identified by its color and cherry red internal reflections under crossed polarized light. According to Dennis Beals (who graciously provided this sample for study), hypogene galena, newly exposed by receding water levels, is sought after by the miners for its silver content. In this sample pyrargyrite is the main silver mineral, though the sample also contains tetrahedrite (in abundance approximately equal to that of pyrargyrite) which may also contain silver. The pyrargyrite grain left of center has a core of gray tetrahedrite.
Polished section, plane polarized light (air), FOV = 0.32 mm. Ben Schumer collection and photo.