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Linus
Joined: 06 Nov 2015
Posts: 61
Location: Tucson
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 Posted: Jul 22, 2021 15:30 Post subject: Re: Black, metallic, yellow oxide? |
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| ferberrite ps scheelite??? |
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Linus
Joined: 06 Nov 2015
Posts: 61
Location: Tucson
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| Posted: Jul 22, 2021 16:58 Post subject: Re: Black, metallic, yellow oxide? |
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... one of Rob's pieces... (oh and the yellow may be tungstite or similar...
"Ferberite Pseudomorph after Scheelite
Ferberite Pseudomorph after Scheelite from Trumbull, Fairfield Co., Connecticut
Collection
Robert Lavinsky
Description
An excellent Ferberite crystal over Scheelite, where the crystal replaced the original mineral. This material came out over 100 years ago, and is considered one of the most classic of East Coast "black uglies," and quite hard to obtain today. This is one of the largest examples, and certainly the best and largest single crystal that I have seen for sale myself by a long run. It is remarkably complete, if a bit crude on some faces, all around.
Locality
Trumbull, Fairfield Co., Connecticut
Dimensions
4.6 x 3.9 x 3.7 cm." |
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Tobi
Site Admin
Joined: 07 Apr 2009
Posts: 4248
Location: Germany
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| Posted: Jul 23, 2021 02:15 Post subject: Re: Black, metallic, yellow oxide? |
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I'm glad that I maybe wasn't that wrong with my scheelite guess ;-)
| Linus wrote: | | ferberite ps scheelite??? |
I think we're on a good way. The ferberite ps. after scheelite - the so-called "reinite" - could really fit: Hardness between 4 and 5, very heavy, non-fluorescent, brownish streak, good cleavage, contains tungsten and iron ... and the crystal form would also match ... |
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Susan Robinson
Joined: 05 Aug 2010
Posts: 163
Location: Hancock, MI
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| Posted: Jul 23, 2021 07:27 Post subject: Re: Black, metallic, yellow oxide? |
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My first guess was a pseudomorph of ferberite or hubnerite after scheelite from Trumbull, CT. Ron Januzzi had a big collection of these at his old rock shop near Brewster, NY, back in the 1980s.
Susan Robinson
_________________
Susan Robinson |
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Linus
Joined: 06 Nov 2015
Posts: 61
Location: Tucson
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| Posted: Jul 23, 2021 17:34 Post subject: Re: Black, metallic, yellow oxide? |
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| with precious little info, I think you did great, than you! |
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Linus
Joined: 06 Nov 2015
Posts: 61
Location: Tucson
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| Posted: Jul 23, 2021 17:36 Post subject: Re: Black, metallic, yellow oxide? |
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| I'm debating on the Connecticut provenance though, could also be Rwanda, Uganda... I'm hoping I may be able to tie that down too. You guys have been very helpful. I'm about 95% convinced on the species (and the yellow oxide too!). Cool that its a rare and interesting piece! |
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Bob Carnein
Joined: 22 Aug 2013
Posts: 355
Location: Florissant, CO
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| Posted: Jul 23, 2021 18:40 Post subject: Re: Black, metallic, yellow oxide? |
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| This is a great find of a classic pseudomorph! Congratulations. |
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Johan Kjellman
Joined: 10 Jan 2014
Posts: 19
Location: Uppsala
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| Posted: Jul 24, 2021 12:18 Post subject: Re: Black, metallic, yellow oxide? |
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| Linus wrote: | | I'm debating on the Connecticut provenance though, could also be Rwanda, Uganda... I'm hoping I may be able to tie that down too. You guys have been very helpful. I'm about 95% convinced on the species (and the yellow oxide too!). Cool that its a rare and interesting piece! |
Apparently there are similar pieces also from French, Portugese and Japanese localities.
cheers |
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Linus
Joined: 06 Nov 2015
Posts: 61
Location: Tucson
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| Posted: Jul 24, 2021 14:52 Post subject: Re: Black, metallic, yellow oxide? |
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| Yes indeed. I'm trying to get some documentation on its possible whereabouts, but we'll have to see how that goes. |
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deadhead
Joined: 19 Mar 2018
Posts: 1
Location: Seminole, FL United States
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| Posted: Oct 26, 2021 15:59 Post subject: Re: black, metallic, yellow oxide? |
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| SteveB wrote: | Magnetite? Yellow oxide it often zinc related and here it may have nothing to do with the crystal itself but from the host matrix. Could be residue from “YellowTak” similar to “BluTak” that rubbery gum stuff you use to stick posters to your wall. Its commonly used to “stick down” mineral samples into small cases. If it is it could be crumbly or maybe still sticky depending on how old it is.
Did you yourself collect this in the field? Where exactly? Or was it given to you or did you buy it? The yellow I’m certain is related to previous adhesive material and nothing to do with mineral. More testing needed like mentioned in the sticky forum thread on what to do before posting a photo and asking what is this. It wastes everyones time and discourages relevant answers. So read that thread and host back with more data.
My guess for now is magnetite. Just a guess. |
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