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Hi Jim, thanks for your reply. Your specimens look great. I did a streak test, and it was black. Maybe it was the silver sulfide coating? My PI ,or the GPZ did pick it up from over a foot, so not sure. Also is there anything I should do the the specimen? To clean? Thank you

Chris

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Sometimes cuprite can appear very dark gray, almost black. Its real hard to do mineral ID by a simple photo - even a good clear one. Cuprite will make your detector sound off at a good distance.  Cuprite is a copper mineral that conducts electricity like a metal. Its often a very dark red but can range to a dark gray almost silver color.

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9 hours ago, Reno Chris said:

Sometimes cuprite can appear very dark gray, almost black. Its real hard to do mineral ID by a simple photo - even a good clear one. Cuprite will make your detector sound off at a good distance.  Cuprite is a copper mineral that conducts electricity like a metal. Its often a very dark red but can range to a dark gray almost silver color.

Thanks Chris, it definitely looks like a copper mineral. I'll keep trying to figure out what it is.

 

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Chris,

  Ill try to get an XRF on it sometime this week, hopefully tomorrow, and let you know.... very cool looking though.

Dave.

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Chris, you now have several possibilities and I'll throw in another, covellite, closely related to 

Steve's  idea of chalcocite. What we collect is usually blue but I have seen some so dark it looks black.

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Hi Chris… it’s a subjective decision, but for whatever it’s worth I wouldn’t do any treatment to your sample. It displays well and is otherwise quite an attractive specimen in its current state. Dave hopefully can satisfactorily identify it for you shortly. 

It is not a simple task to identify your mineral based on a photograph. A black streak test result implies a mineral compound, and not strictly a native metal. Some non-metal minerals do react to both VLF and PI units, producing good metalliferous type signals. In northeastern Ontario, these include solidly structured pyrrhotite, niccolite, cobalt, safflorite, skutterudite, and quite a number of potential silver-cobalt-nickel-iron-arsenide mineral permutations that you will never encounter in generally circulated mineralogical texts.

The silver mineral combinations are sufficiently complex and numerous as to require a reference list from the local museum, and more sophisticated identification techniques are required than the common mineral field tests normally available to hobbyists. We can easily imagine that such minerals would present insurmountable identification issues for hobbyists in the field and certainly the same applies in the context of forum discussion here.

Many of these minerals freshly exposed would produce a similar appearance to the silvery material in your photo. But the primarily cobalt-nickel-iron-arsenide related minerals do not necessarily account for the black host material in your photo with any real confidence. And frankly, I have no idea if these mineral types potentially even exist in your search areas.

There are other suggestions above, such as the enriched copper sulfides (bornite-covellite-chalcocite) that do produce VLF target signals, but do not react to my PI units. Unfortunately I’m not familiar with GPZ responses to various minerals because we have no hands-on experience with it to date.

Attached are a few mineral examples mentioned in this thread including a photo of low-grade cuprite (it’s all I’ve got). Chris R. above makes a perfectly viable case for this mineral’s consideration. Thanks for an interesting topic, it’s been an enjoyable diversion to post our possible solutions for you!!! :cool:

1598368181_1.8OZTCHALCOCITESF16YGLASS.JPG.556b4a40b588feb06c321ba6ba0658b7.JPG

1412359132_0.4LBCOVELLITESF14BB.JPG.82b13ec6a7ade0bc470951c80d940bc2.JPG

1985849064_0.9OZTLOW-GRADECUPRITETWOSF17GG.JPG.747236915d0e2d7ab4e9bf74dd85404d.JPG

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1 hour ago, Jim Hemmingway said:

Hi Chris… it’s a subjective decision, but for whatever it’s worth I wouldn’t do any treatment to your sample. It displays well and is otherwise quite an attractive specimen in its current state. Dave hopefully can satisfactorily identify it for you shortly. 

It is not a simple task to identify your mineral based on a photograph. A black streak test result implies a mineral compound, and not strictly a native metal. Some non-metal minerals do react to both VLF and PI units, producing good metalliferous type signals. In northeastern Ontario, these include solidly structured pyrrhotite, niccolite, cobalt, safflorite, skutterudite, and quite a number of potential silver-cobalt-nickel-iron-arsenide mineral permutations that you will never encounter in generally circulated mineralogical texts.

The silver mineral combinations are sufficiently complex and numerous as to require a reference list from the local museum, and more sophisticated identification techniques are required than the common mineral field tests normally available to hobbyists. We can easily imagine that such minerals would present insurmountable identification issues for hobbyists in the field and certainly the same applies in the context of forum discussion here.

Many of these minerals freshly exposed would produce a similar appearance to the silvery material in your photo. But the primarily cobalt-nickel-iron-arsenide related minerals do not necessarily account for the black host material in your photo with any real confidence. And frankly, I have no idea if these mineral types potentially even exist in your search areas.

There are other suggestions above, such as the enriched copper sulfides (bornite-covellite-chalcocite) that do produce VLF target signals, but do not react to my PI units. Unfortunately I’m not familiar with GPZ responses to various minerals because we have no hands-on experience with it to date.

Attached are a few mineral examples mentioned in this thread including a photo of low-grade cuprite (it’s all I’ve got). Chris R. above makes a perfectly viable case for this mineral’s consideration. Thanks for an interesting topic, it’s been an enjoyable diversion to post our possible solutions for you!!! :cool:

1598368181_1.8OZTCHALCOCITESF16YGLASS.JPG.556b4a40b588feb06c321ba6ba0658b7.JPG

1412359132_0.4LBCOVELLITESF14BB.JPG.82b13ec6a7ade0bc470951c80d940bc2.JPG

1985849064_0.9OZTLOW-GRADECUPRITETWOSF17GG.JPG.747236915d0e2d7ab4e9bf74dd85404d.JPG

 

On 1/8/2019 at 7:46 AM, Steve Herschbach said:

Possibly chalcocite, another conductive copper mineral, and dark grey color more the norm.

 

17 hours ago, Bob(AK) said:

Chris, you now have several possibilities and I'll throw in another, covellite, closely related to 

Steve's  idea of chalcocite. What we collect is usually blue but I have seen some so dark it looks black.

 

On 1/7/2019 at 9:45 PM, Reno Chris said:

Sometimes cuprite can appear very dark gray, almost black. Its real hard to do mineral ID by a simple photo - even a good clear one. Cuprite will make your detector sound off at a good distance.  Cuprite is a copper mineral that conducts electricity like a metal. Its often a very dark red but can range to a dark gray almost silver color.

These were the test results on the scan20190109_163555.thumb.jpg.a972e40c943c1127d7d97e4a821460f3.jpg

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