5
typical Ni-Co-Fe trend for skutterudite group minerals.
The later stage sulfide minerals, however, contain roughly
equal concentrations of nickel and cobalt as sulfide seem-
ingly exsolving from the acanthite. At Cobalt, the late stage
arsenides are cobalt dominant, and have much more vari-
able compositions, with up to several percent components
of sulfur, antimony, and bismuth. Their metal to arsenic
ratio has presented challenges for their accurate identi-
fication, and further analysis is required. Lastly, the later
arsenides at Cobalt precipitate in two distinct phases, both
cobalt dominant, but with quite different metal to arsenic
ratios. At Black Hawk, nickelskutterudite is prevalent, and
the composition only varies within the constraints of the
species, and forms alternating bands of nickelskutterudite
and carbonate gangue in places along the arsenide-gangue
boundaries. This texture is not observed at Cobalt. Both
deposits display the hallmarks for a five-element style
hydrothermal vein system, and as more details are explored
this assessment will be further refined.
REFERENCES
[1] Gillerman, E., &Whitebread, D. H. (1953). The
uranium-bearing nickel-cobalt-native silver depos-
its in the Black Hawk district, Grant County, New
Mexico. In Trace Elements Investigations (261). U.S.
Geological Survey. doi.org/10.3133/tei261
[2] Kissin, S. A. (1992). Five-element (Ni-Co- As-Ag-Bi)
Veins.
[3] Markl, G., Burisch, M., &Neumann, U. (2016).
Natural fracking and the genesis of five-element
veins. Mineralium Deposita, 51(6), 703–712. doi
.org/10.1007/s00126-016-0662-z
[4] Oen, S., Dunn, P. J., &Kieft, C. (1984). The nickel-
arsenide assemblage from Franklin, New Jersey:
Description and interpretation. The Nickel-Arsenide
Assemblage from Franklin, New Jersey: Description and
Interpretation, 150(3), 259–272.
[5] Von Bargen, D. J. (1979). The Silver- Antimony-
Mercury System and the Mineralogy of the Black Hawk
[6] District, New Mexico -ProQuest.
[7] www.proquest.com/openview/4f438ad5acf86cd53fa
cac6d0b4a73ef/1.pdf?pq- origsite=gscholar&cbl=18
750&diss=y
[8] Gerwe, J. E. (1986). Ag-Ni-Co-As-U
[9] Mineralization in the Black Hawk Mining District,
Grant County, New Mexico (Doctoral dissertation,
New Mexico Institute of Mining and Technology).
[10] Burton, J. (2022). U.S. Geological Survey Releases
2022 List of Critical Minerals. www.usgs.gov
/news/national-news-release/us-geological-survey
-releases-2022- list-critical-minerals
Table 7. List of minerals and respective chemical formulae.
*Discredited species by International Mineralogical
Association (IMA)
Acanthite Ag2S
Allargentum (Ag1-xSbx) (x ≈ 0.09-0.16)
Bravoite* (Fe,Ni)S2
Breithauptite NiSb
Chloanthite* (Ni,Co,Fe)As2-2.5
Dyscrasite Ag3Sb
Ferroskutterudite (Fe,Co)As3
Nickeline NiAs
Nickelskutterudite (Ni,Co,Fe)As
3
Pearceite [Ag6As2S7][Ag9CuS4]
Rammelsbergite NiAs2
Safflorite (Co,Ni,Fe)As
2
Skutterudite CoAs3
Smaltite* CoAs3-x
typical Ni-Co-Fe trend for skutterudite group minerals.
The later stage sulfide minerals, however, contain roughly
equal concentrations of nickel and cobalt as sulfide seem-
ingly exsolving from the acanthite. At Cobalt, the late stage
arsenides are cobalt dominant, and have much more vari-
able compositions, with up to several percent components
of sulfur, antimony, and bismuth. Their metal to arsenic
ratio has presented challenges for their accurate identi-
fication, and further analysis is required. Lastly, the later
arsenides at Cobalt precipitate in two distinct phases, both
cobalt dominant, but with quite different metal to arsenic
ratios. At Black Hawk, nickelskutterudite is prevalent, and
the composition only varies within the constraints of the
species, and forms alternating bands of nickelskutterudite
and carbonate gangue in places along the arsenide-gangue
boundaries. This texture is not observed at Cobalt. Both
deposits display the hallmarks for a five-element style
hydrothermal vein system, and as more details are explored
this assessment will be further refined.
REFERENCES
[1] Gillerman, E., &Whitebread, D. H. (1953). The
uranium-bearing nickel-cobalt-native silver depos-
its in the Black Hawk district, Grant County, New
Mexico. In Trace Elements Investigations (261). U.S.
Geological Survey. doi.org/10.3133/tei261
[2] Kissin, S. A. (1992). Five-element (Ni-Co- As-Ag-Bi)
Veins.
[3] Markl, G., Burisch, M., &Neumann, U. (2016).
Natural fracking and the genesis of five-element
veins. Mineralium Deposita, 51(6), 703–712. doi
.org/10.1007/s00126-016-0662-z
[4] Oen, S., Dunn, P. J., &Kieft, C. (1984). The nickel-
arsenide assemblage from Franklin, New Jersey:
Description and interpretation. The Nickel-Arsenide
Assemblage from Franklin, New Jersey: Description and
Interpretation, 150(3), 259–272.
[5] Von Bargen, D. J. (1979). The Silver- Antimony-
Mercury System and the Mineralogy of the Black Hawk
[6] District, New Mexico -ProQuest.
[7] www.proquest.com/openview/4f438ad5acf86cd53fa
cac6d0b4a73ef/1.pdf?pq- origsite=gscholar&cbl=18
750&diss=y
[8] Gerwe, J. E. (1986). Ag-Ni-Co-As-U
[9] Mineralization in the Black Hawk Mining District,
Grant County, New Mexico (Doctoral dissertation,
New Mexico Institute of Mining and Technology).
[10] Burton, J. (2022). U.S. Geological Survey Releases
2022 List of Critical Minerals. www.usgs.gov
/news/national-news-release/us-geological-survey
-releases-2022- list-critical-minerals
Table 7. List of minerals and respective chemical formulae.
*Discredited species by International Mineralogical
Association (IMA)
Acanthite Ag2S
Allargentum (Ag1-xSbx) (x ≈ 0.09-0.16)
Bravoite* (Fe,Ni)S2
Breithauptite NiSb
Chloanthite* (Ni,Co,Fe)As2-2.5
Dyscrasite Ag3Sb
Ferroskutterudite (Fe,Co)As3
Nickeline NiAs
Nickelskutterudite (Ni,Co,Fe)As
3
Pearceite [Ag6As2S7][Ag9CuS4]
Rammelsbergite NiAs2
Safflorite (Co,Ni,Fe)As
2
Skutterudite CoAs3
Smaltite* CoAs3-x