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Identity HelpMy discovery!?
5th Mar 2013 02:46 UTCNorman King 🌟 Expert
I have two questions (well, maybe two and a half):
1. Does anyone know of reports of malachite occurring at Sweetwater? Or, is there some other mineral there that mimics malachite?
2. Assuming you all agree with my identification, would this merit addition to the list of Sweetwater minerals, in view of the fact I have no analyses? (I am fully aware of how many green copper carbonates, phosphates, etc. there are!)
I’d like to upload this photo to the gallery, and add malachite to the mineral list for that locality, but I wonder how the managers would view this.
5th Mar 2013 10:22 UTCKeith A. Peregrine 🌟
Keith
5th Mar 2013 20:31 UTCRob Woodside 🌟 Manager
5th Mar 2013 22:56 UTCNorman King 🌟 Expert
You sound like a true skeptic. (Ah, the lessons of experience, right?)
All of the crystals that are broken are golden yellow on the inside but covered with bluish tarnish externally. You can see them in the lower part of photo "chalco3d,25.1mm-r.jpg (371.5 KB)." You can also see in those crystals that the tarnish goes into them a short distance, then fades. A few patches of dolomite are also covered with those spots that look like green chicken-pox.
I acquired the specimen from Dan Weinrich, who sells a lot of Sweetwater mine specimens. He posted one photo (273977) with a child of a specimen that has the tabular crystals but little or no tarnish, if that might help.
6th Mar 2013 00:10 UTCMatt Neuzil Expert
I'm staying with the law. "innocent until proven guilty"
6th Mar 2013 00:28 UTCEugene & Sharon Cisneros Expert
Gene
6th Mar 2013 01:10 UTCNorman King 🌟 Expert
OK, I give--why wouldn't it?
Does that relate to whether it was a natural process or not?
Does that have a bearing on whether it is malachite or not?
I'm not arguing, I'm just wondering. (Like I said, it's an interesting question.)
Another point Matt raised: How many other Sweetwater mine pieces have these spots? I didn't notice them until I spent some time with my specimen under the microscope. Originally I photographed it with my Canon SX10-IS with macro lens here at the house. My photo (photomicrograph) labels above include the field of view for each one. Doing a little measuring on the photos and simple math, I came up with a size range of the spots from about 0.02 to 0.04 mm, or from 25 to 50 per mm. Those would be difficult to see without the microscopic examination, and they might have escaped notice. So, can we ever really answer that last question?
6th Mar 2013 15:48 UTCKelly Nash 🌟 Expert
As far as acid treatment to get the blue tarnish, I've seen many pieces with gaudy blue chalcopyrite enncrusting parts of lustrous calcite crystals, I don't really think they're going in an acid bath. I've quizzed Dan myself about whether these irridescent chalcopyrites are chemically treated, and he insists that the miners he knows don't have the time or inclination to do this, and many have seen them in place. Also, I've seen huge, flawless, calcites with very tiny blebs of bright blue chalcopyrite on them. In my opinion, there would have been no reason to treat those specimens in a chemical bath, and risk dinging the calcite crystal tips, just to get a tiny spot of irridescent chalcopyrite on the backside.
6th Mar 2013 17:55 UTCBob Harman
6th Mar 2013 18:39 UTCHarold (Hal) Prior Expert
6th Mar 2013 21:17 UTCKevin Conroy Manager
However, I also know for a fact that some of the miners do treat the chalcopyrites to enhance the color. Some use a diluted mix of Drain-o (or other similar products), some use a diluted mix of vinegar and copper scraps, and others use diluted acid solutions.
So, is the malachite on the pictured chalcopyrite natural or not? I don't know!
7th Mar 2013 03:24 UTCHarold (Hal) Prior Expert
8th Mar 2013 00:37 UTCStephen C. Blyskal Expert
I've suspected every since the tarnished chalcopyrites started showing up on the market a few years ago that someone was treating them to get that color. I've seen massive chalcopyrite treated and sold as "bornite" or "peacock ore" for many years at rock shops, etc. I wondered because in almost 40 years of acquiring Viburnum Trend specimens I had never run across this color chalcopyrite before. It was always a bright, brassy color on the best specimens. Glad I got my originals early, since I doubt we'll see any untreated specimens anymore. Yes, I've added a few of these to my collection, but don't like the upcharge in prices as a result of making them "prettier".
8th Mar 2013 01:38 UTCBob Harman
BTW, at least one high end dealer currently, and over the past couple of years, has been selling many, many examples of these multicolored peacock ore specimens. CHEERS.........BOB
8th Mar 2013 02:34 UTCKevin Conroy Manager
Bob, I think almost all of the extremely brightly colored ones that you see at the shows have been treated. I know of a major wholesaler of minerals who was treating these (starting about 5 years or so ago) after getting them back to his home base from the miners. I don't know if he in particular is still doing it, but it looks like the market is flooded with these colorful chalcopyrites.
The mines of the Viburnum Trend produced, and continue to produce, really outstanding mineral specimens. I used to wholesale and retail these minerals so I made regular trips to see the miners. Since I live in the St Louis area I'm only a few hours away from even the southern-most end of the Trend. I've had some very good naturally iridescent chalcopyrites through the years but even the best of these don't compare in color to the hoard of specimens available now. As far as telling the natural from the enhanced, if it looks unnatural it most likely is.
8th Mar 2013 16:20 UTCStephen C. Blyskal Expert
I'll have to take some photos of some of the brassy yellow chalcopyrites I've picked up over the years. My best one, a solid mass with no matrix over 6" long, came from Chris Wright, of all people. I got many from Glenn Williams when he used to do shows with Hal Prior in Clear Lake many, many years ago. I will look through my old ones, but off-hand I don't remember seeing any with colors before this latest group of high priced specimens hit the market.
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Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: March 28, 2024 09:23:11