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Tracy
Joined: 15 Sep 2006
Posts: 551
Location: Toronto
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Posted: Dec 31, 2008 11:37 Post subject: Re: Why is this wulfenite silver? |
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I can do a peroxide test, bur for lack of proper equipment/chemicals to do the other diagnostics (when next I see you Alfredo I'll bring it with me), I'm going with the temporary premise that the silver is a coating (which in parts has a rippled appearance under a loupe, like paint) and that beneath the silver is a rough-textured, second red coating - suggesting that the crystal, whatever color it is, is coated with hematite or iron oxides. I don't see any smooth areas (besides the silver ones) to tell me with certainty what the color might be beneath all the coating(s). All the same, as an empirical question, is it theoretically possible to have a wulfenite crystal that is included with hematite? Maybe I'll carefully try to scratch one of the red edges (close to where it contacts the matrix), that might help.
I did test it with a magnet and if the stuff is magnetic, it's only very weakly so.
_________________ "Wisdom begins in wonder" - Socrates |
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Peter Megaw
Site Admin
Joined: 13 Jan 2007
Posts: 963
Location: Tucson, Arizona
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Posted: Dec 31, 2008 13:24 Post subject: Re: Why is this wulfenite silver? |
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Les, given your experiences in Arizona copper mines you should know the old handspecimen trick of putting a couple drops of HCl from your field bottle onto suspected copper-bearing "limonites" and skootching it around with straightpin (knifeblade) to see if copper plates out. fast dirty and very accurate
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Linda St-Cyr
Joined: 29 Oct 2008
Posts: 34
Location: Sparks, Nevada & on the road!
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Posted: Dec 31, 2008 18:11 Post subject: Re: Why is this wulfenite silver? |
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Alfredo & Pete - thank you for some cool ideas for my science museum! Now I have an excuse to save all those little bits of minerals lying around. (Actually I was already saving them to try the ID by flame method.)
_________________ Linda St-Cyr |
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Tracy
Joined: 15 Sep 2006
Posts: 551
Location: Toronto
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Posted: Jan 03, 2009 18:59 Post subject: Re: Why is this wulfenite silver? |
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Peroxide test was negative, and I don't really want to start scraping at it unless I have to...guess I'll have to wait till I can show it to someone...
_________________ "Wisdom begins in wonder" - Socrates |
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David Catalano
Joined: 11 Nov 2009
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Posted: Nov 12, 2009 10:13 Post subject: Re: Why is this wulfenite silver? |
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Hello,
There are a few colors of wulfenite found at Tsumeb, however in early mining operations a blue tinged var. of wulfenite was found. It was known to have a metallic luster. Your specimen looks like bicolor wulfenite. It seems to have sections of color. Awesome piece that you have there. Tsumeb is known for amazing, world class mineral semblances.
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Tracy
Joined: 15 Sep 2006
Posts: 551
Location: Toronto
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Posted: Nov 12, 2009 10:22 Post subject: Re: Why is this wulfenite silver? |
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Thanks for the info David!
- Tracy
_________________ "Wisdom begins in wonder" - Socrates |
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Matt_Zukowski
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Joined: 10 Apr 2009
Posts: 707
Location: Alaska
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Posted: Nov 13, 2009 00:14 Post subject: Re: Why is this wulfenite silver? |
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What a great thread! Interesting chemistry - thanks.
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Val
Joined: 06 May 2009
Posts: 15
Location: Upstate NewYork
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Posted: Nov 13, 2009 16:48 Post subject: Re: Why is this wulfenite silver? |
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I thought you might want to see some photos of my blue Wulfenite from Tsumeb. As you can see it looks metallic with a bluish sheen.
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