Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography
╳Discussions
💬 Home🔎 Search📅 LatestGroups
EducationOpen discussion area.Fakes & FraudsOpen discussion area.Field CollectingOpen discussion area.FossilsOpen discussion area.Gems and GemologyOpen discussion area.GeneralOpen discussion area.How to ContributeOpen discussion area.Identity HelpOpen discussion area.Improving Mindat.orgOpen discussion area.LocalitiesOpen discussion area.Lost and Stolen SpecimensOpen discussion area.MarketplaceOpen discussion area.MeteoritesOpen discussion area.Mindat ProductsOpen discussion area.Mineral ExchangesOpen discussion area.Mineral PhotographyOpen discussion area.Mineral ShowsOpen discussion area.Mineralogical ClassificationOpen discussion area.Mineralogy CourseOpen discussion area.MineralsOpen discussion area.Minerals and MuseumsOpen discussion area.PhotosOpen discussion area.Techniques for CollectorsOpen discussion area.The Rock H. Currier Digital LibraryOpen discussion area.UV MineralsOpen discussion area.Recent Images in Discussions
GeneralFor the Love of Dendrites
19th Aug 2012 08:17 UTCStephanie Martin
This thread is being dedicated to the lovely form of dendrites. Initially this began as an appreciation of manganese oxides, however I invite any kind of dendrites to be shared here. In addition since dendrites are well suited for lapidary purposes and are poplular as such, these are also welcomed to be shared here.
Here are a few to start the parade. I left out Solnhofen deliberately since I am sure many of you would have wonderful ones to contribute and I would love to see them.
This first one is from Utah, USA, if anyone knows a more specific location please let me know.
Approx 10 x 9 cm
Rockydale Quarry
Roanoke, Virginia, USA
label indicates collected 7/11/1996
6 x 4 cm
Matachewan,
Ontario, Canada
6 x 2cm
19th Aug 2012 08:23 UTCStephanie Martin
Dřínová, Tišnov, Moravia, Czech Republic
Czech Republic
7.8 x 5.5 cm
Some lapidary items...
Cuprite Dendrites in Pectolite (larimar)
Dominican Republic
2 x 2 cm
Dendrites in Chrysocolla with Malachite
location unknown
18 mm x 14 mm
19th Aug 2012 11:14 UTCRoberto Bosi
The second specimen is an ammonite (diameter 30 mm) crossed by well defined dendrites. I hope you like it.
19th Aug 2012 11:35 UTCRock Currier Expert
Why don't you write an article about dendrites? At the very least you should write up a better definition for our glossary than the one we have and show some more pictures of them.
19th Aug 2012 12:46 UTCAgustin Agudo Espinosa
I think for many, was the first samples, we began to captivate.
Here is a copy of manganese oxides from Jalapa Mine in El Molar, Tarragona, Catalonia, Spain.
Greetings to all.
Agustin Agudo Espinosa.
19th Aug 2012 13:43 UTCRui Nunes 🌟 Expert
19th Aug 2012 15:19 UTCKelly Nash 🌟 Expert
http://www.mindat.org/forum.php?file,17,file=40084,filename=Dendrites-sml.jpg
19th Aug 2012 15:59 UTCNorman King 🌟 Expert
19th Aug 2012 17:36 UTCStephanie Martin
Rock, I will eventually put together an article, would like to see what interesting things may turn up on this thread in the meantime.
regards,
stephanie :-)
19th Aug 2012 18:12 UTCAgustin Agudo Espinosa
A.Agudo Espinosa.
19th Aug 2012 18:35 UTCRui Nunes 🌟 Expert
I bet 99,99 % that this is not a dendrite neither a limestone specimen. It seems man made something like a drawing inspired in a limestone landscape and in the dendrites effects. Buildings, people, trees, birds, all in the right place... not natural for me.
Cheers
19th Aug 2012 20:29 UTCJohn R. Montgomery 🌟 Expert
John
19th Aug 2012 20:41 UTCAntónio Manuel Ináçio Martins
Some Dendrites of my collection : http://www.mindat.org/user-3851.html#2_0_26645_0_0_0_
Regards.
Martins da Pedra
19th Aug 2012 21:14 UTCDean Allum Expert
Stephanie, do these fit the definition of mimetoliths?
While I don't have any worthy manganese dendrites, this fluorite pattern is reminiscent of dendrites.
-Dean Allum
http://www.mindat.org/photos/0488935001293913634.jpg
19th Aug 2012 21:41 UTCStephanie Martin
Dean, I would assume that they would qualify because they do resemble trees or ferns or such. And I do believe you have a worthy example of dendrites, and the spodumene they have formed on makes a nice contrastive canvas.
http://www.mindat.org/photo-357307.html
cheers,
stephanie :-)
19th Aug 2012 21:55 UTCRui Nunes 🌟 Expert
20th Aug 2012 00:38 UTCDan R. Lynch
20th Aug 2012 03:28 UTCMarc Miterman (2)
I have always loved Dendrites.
This specimen has been in my collection since 1971.
Pyrolusite Dendrite
Eichstatt, West Germany
16 cm x 9 cm
20th Aug 2012 11:55 UTCTom Goodland
I recently found some calcite crystals with distinct presumably manganese oxide dendritic growths on several of the crystal faces. I have found similar dendritic growths from several different locations, where they had been caused by solutions seeping between bedding planes, but i'm mystified how these particular dendrites could have formed. Has anyone else seen dendrites on crystal faces?
Sorry no photos at present, all my specimens are in storage.
thanks
tom goodland
20th Aug 2012 15:43 UTCBoris Erjavc
here are some of calcites with probably manganeze dendrites on crystal faces.
Mežica Mine,Slovenia:
Back side, same specimen:
Jasovnik tunnel, Slovenia. 3 × 3.5 × 3 cm
Specimen was all embeded in clay.
Good luck
Boris
20th Aug 2012 17:29 UTCRob Woodside 🌟 Manager
20th Aug 2012 18:52 UTCRock Currier Expert
20th Aug 2012 19:15 UTCStephanie Martin
Rob, you say you "lost" those, I hope they went to good homes. Thanks for sharing your mementos.
20th Aug 2012 19:38 UTCRob Woodside 🌟 Manager
21st Aug 2012 01:44 UTCRaúl Jorge Tauber Larry
FOV: 4 x 4 mm.
From "Puesto Viejo" Quarry, Sierra de Puesto Viejo, Santa Bárbara Department, Province of Jujuy, Argentina.
Collected in 2004.
21st Aug 2012 01:54 UTCRaúl Jorge Tauber Larry
Specimen size: 12,7 x 9 x 1.8 cm.
From Raco River, Trancas Department, Province of Tucumán, Argentina.
Collected in 2010.
21st Aug 2012 01:57 UTCRaúl Jorge Tauber Larry
Specimen size: 6.7 x 4 x 2.1 cm.
From Salar del Hombre Muerto, Antofagasta de la Sierra Department, Province of Catamarca, Argentina.
Collected in 2002.
21st Aug 2012 02:00 UTCRaúl Jorge Tauber Larry
Specimen size: 7 x 4 x 2,3 cm.
From "Loro" River, Burruyacú Department, Province of Tucumán, Argentina.
Collected in 80´s.
21st Aug 2012 02:04 UTCRaúl Jorge Tauber Larry
Specimen size: 19.5 x 11 x 0.5 cm.
From Salar del Hombre Muerto, Antofagasta de la Sierra Department, Province of Catamarca, Argentina.
Collected in 2004.
21st Aug 2012 03:59 UTCStephanie Martin
Tom - regarding growth on crystals, I think it depends on the type of crystal and the environment in which the dendrites form. Dendrites are seen frequently on feldspars and I think it might have to do with the actual surface of the crystal. Certainly they seem to like more porous surfaces, perhaps that is a coincidence based on the nature of the deposits where they are more typically found. But you are are right, you don't see them much on gem type crystals, more in them than on them, especially quartz. I suspect this might have to do with secondary deposition conditions and these don't seem to favour them forming and adhering to gem crystals in their environs.
Here is a feldspar with some incipient dendrites in what I call the blotchy stage.
Orthoclase twin
Cinco, Kern Co, California USA
4 x 2.5cm ex Fred Devito
21st Aug 2012 04:16 UTCStephanie Martin
There has been a lot of this Chinese jasper out there, they look so much like paintings, so I had to get one of course. 10 x 4cm.
And the great thing is that it has two sides that can both be displayed, which side to choose? Or should I get one of those spinning frames? LOL.
cheers,
stephanie :))
21st Aug 2012 05:28 UTCStephanie Martin
Fossil Clam
Indonesia
4.3 x 2.8cm
21st Aug 2012 07:44 UTCCorie Mattar
Here is a lemon opal dendrite from the Knoxville Recreation Area north of Napa California.
25th Aug 2012 17:51 UTCStephanie Martin
Colonial Mine
Cape D'Or, Cumberland Co, Nova Scotia, Canada
~3cm
Aborescent Silver coated with Safflorite
Millerette Mine, Haultain Township, Gowganda area, Cobalt-Gowganda region, Timiskaming District, Ontario, Canada
~2cm
26th Aug 2012 02:32 UTCRaúl Jorge Tauber Larry
FOV: 10 x 5 mm.
From Madagascar.
26th Aug 2012 02:56 UTCRaúl Jorge Tauber Larry
Specimen size: 9.5 x 9 x 4.6 cm.
From Copiapó, Copiapó Province, Atacama Region, Chile.
Collected in 1996.
26th Aug 2012 02:58 UTCRaúl Jorge Tauber Larry
Specimen size: 10.5 x 6.5 x 6 cm.
From Copiapó, Copiapó Province, Atacama Region, Chile.
Collected in 1996.
26th Aug 2012 03:01 UTCRaúl Jorge Tauber Larry
Specimen size: 5.6 x 2 x 1.1 cm.
From Osceola Shaft # 10, Calumet, Houghton County, Michigan, U.S.A.
26th Aug 2012 03:11 UTCRaúl Jorge Tauber Larry
Specimen size: 7.5 x 6 x 4.5 cm.
From La Providencia Mine, Susques Department, Province of Jujuy, Argentina.
Collected in 60´s.
26th Aug 2012 06:55 UTCStephanie Martin
Here are some cryptomelanes. I have posted these before but couldn't resist posting again for the dendrite cause.
Cryptomelane
Pitorra mine, Galiléia, Minas Gerais, Brazil
Longest dendrite 28mm
faceted stone is 15mm x 10mm (unknown dendrite type), Brazil
26th Aug 2012 07:02 UTCStephanie Martin
Moss Opal
Nasławice, Gogołów-Jordanów Massif, Lower Silesia (Dolnośląskie), Poland
~4.5 x 4.5cm
The next two are from the same location, Czech Republic.
Bohouskovice, České Budějovice (Budweis), South Bohemia Region, Bohemia (Böhmen; Boehmen), Czech Republic
3.0 x 1.5 cm
2.0 x 1.5 cm
26th Aug 2012 14:05 UTCjulie g. powell
cedar City Iron county ,Utah Check out Dave Crosby site for maps and locations. I have been looking for dendrites in agate ( good one) in the east hills around Summitt Utah A very large area for agate, it goes all the way up the mountain to Brian Head Happy Hunting/size>
26th Aug 2012 14:08 UTCjulie g. powell
cedar City Iron county ,Utah Check out Dave Crosby site for maps and locations. I have been looking for dendrites in agate ( good one) in the east hills around Summitt Utah A very large area for agate, it goes all the way up the mountain to Brian Head Happy Hunting/size>
26th Aug 2012 15:48 UTCBart Cannon
They seem to be natural fractals, and I have a hunch that they grow quickly and, as Bacteria Bart, I think there is an organic aspect to their formations, but I have never heard of mangenese metabolizing bacteria.
I tried an experiment. I crushed up some dirty manganese oxides, emusled them in rainwater, moistened some microscope slides in the suspension and waited almost a year for something to happen. Nothing happened.
It seems as though they most commonly form in fractures in carbonate rocks. I wonder it those carbonate rocks are most often manganese bearing.
My next effort will be to create some little slabs of manganese bearing carbonate rock, join them, and put them in dirty rainwater and leave them alone for at least a year.
Are there non manganese oxide examples of dendrites ?
Bart
.
26th Aug 2012 16:09 UTCStephanie Martin
And yes, they are natural fractals.
26th Aug 2012 17:20 UTCBart Cannon
I can't tell if your cryptomelanes are beautiful or creepy. I'll stick with fascinating.
I have an intuition that dendrites form by capillary activity (wicking).
My next experiment in growing my own dendrites will be to split some fine grained carbonate rocks and bind the pieces back together rather than ginding and mating some small slabs. That should improve the "gription" and improve my chances of becoming the first dendrite artist. A goal with no practical value. My specialty.
Maybe I'll use some weak manganese sulfate solution with the rainwater.
Bart
26th Aug 2012 23:09 UTCAlex Homenuke 🌟 Expert
27th Aug 2012 03:24 UTCBart Cannon
That's very funny, i retract my statement about no practical value for dendrites..
A completely natural and random source for Rorschack images.
I will would work on Rorschack pairs during first day of retirement. Except that would be a day after I'm dead.
I don't know how to spell that guy's name either.
I seem to think that Ruggles Mine uraninite, gummite specimens show a dendritic nature.
The difference between dendritic and arborescent features would seem to be two dimensions vs. three dimensions.
Bart
27th Aug 2012 04:07 UTCStephanie Martin
Wicking may be a factor in the creation of surface dendrites as per your instinctual hunch.
And FYI the correct spelling is Rorschach. I would think that inkblots are essentially fractals as well.
27th Aug 2012 11:40 UTCMaggie Wilson Expert
-------------------------------------------------------
>
>
> The difference between dendritic and arborescent
> features would seem to be two dimensions vs. three
> dimensions.
>
> Bart
a-HA! - Answers a question that I've been pondering since the start of this thread - thanks, Bart!
Maggie
28th Aug 2012 14:33 UTCMaggie Wilson Expert
Dendrites, eh? Ok, here we go! The display face of this specimen has been cut and polished to show off the dentritic effect.
29th Aug 2012 03:35 UTCStephanie Martin
Well it seems I keep finding those dendrite things turning up everywhere. :-D
Here's another featuring arborescent copper in gypsum.
Mission complex, San Xavier, Pima District (Olive District; Mineral Hill District; Twin Buttes District), Sierrita Mts, Pima Co., Arizona, USA
FOV 1.5 cm
29th Aug 2012 07:07 UTCRick Dalrymple Expert
Here are a few...
Rick
29th Aug 2012 13:16 UTCMaggie Wilson Expert
I love the structural aspect of these specimens and they LOVE to be photographed.
Castle Mine
Cobalt-Gowganda region, Ontario, Canada
2.6 x 2.0 x 0.8 cm
29th Aug 2012 15:56 UTCAlexis Monnerot
30th Aug 2012 06:36 UTCRick Dalrymple Expert
30th Aug 2012 06:48 UTCRick Dalrymple Expert
30th Aug 2012 20:34 UTCRick Dalrymple Expert
31st Aug 2012 11:59 UTCMaggie Wilson Expert
31st Aug 2012 14:10 UTCClifford Trebilcock
Here is a photo of some Dendrites in translucent Quartz I collected from an unnamed Feldspar prospect in Center Minot,Maine.
It is about 9 X 6 CM in size and the Dendrites are both on the surface and along internal fractures. Many great photos of Dendrites on this thread.
Cliff
1st Sep 2012 06:21 UTCStephanie Martin
Rick - thanks for sharing so many, you made my day.
Maggie – a nice local surpise, and from a location that is usually known for orange celestite. Just wonderful!
Cliff, that is a stunning unspoiled dendritic quartz! Hope you plan to keep it that way!
More on opals. You often see this material used for cabachons, pendants, earrings etc, but I just find the centers are fascinating on these dendritic opal nodules from Turkey. The chalcedony layer adds some interesting contrast and is fluorescent.
Eskişehir Province, Central Anatolia Region, Turkey
7 x 5 cm and 5.5 cm
1st Sep 2012 23:30 UTCDean Allum Expert
That's a beautiful specimen! It's good to see that you have finally developed an appreciation for mineralogy and some healthy curiosity.
Unless you have just illegally posted a copyrighted picture which you do not own. THEN SHAME ON YOU!! :-X
2nd Sep 2012 06:56 UTCStephanie Martin
stephanie
2nd Sep 2012 11:02 UTCJohn M Stolz Expert
I think you're confusing "appreciation" with "aesthetics". I actually have both. What I seem to be missing is good judgement.
Steph,
Apologies; it didn't occur to me that I would cheat you by posting your picture. 4 pages of posts went by and I never saw it. I was under the impression that this was all about knowledge for knowledge's sake.
To both of you,
1. There was no intention on my part of claiming "credit" for a photo that doesn't belong to me. Hover your mouse over the picture and see what you see,
2. There's always a danger with the written form of communication for miscommunication to occur. For my part, I apologize for having taken the liberty of assuming you would find my clownish actions amusing and in good spirit, instead of insulting. You can be assured I won't take such liberties in the future. Especially now that it seems clear that all I'm doing is making an idiot of myself by having to post a public apology.
2nd Sep 2012 15:20 UTCRaúl Jorge Tauber Larry
FOV: 5 x 4 mm.
From Pegmatite of Milagro Mine, Cerro Pichao, Sierra de Quilmes, Tafí del Valle Department, Province of Tucumán, Argentina.
Collected in 1973.
FOV: 5 x 5 mm.
2nd Sep 2012 17:01 UTCRaúl Jorge Tauber Larry
From pegmatite of "Milagro" Mine, Cerro Pichao, Sierra de Quilmes, Tafí del Valle Department, Province of Tucumán, Argentina.
FOV: 4 x 5 mm.
2nd Sep 2012 17:56 UTCStephanie Martin
Regarding the specimen, I was going to get around to it posting it again eventually, but it was nice to see it. I have enough dendrite material to post one everyday for the remainder of the year if I wanted to, but will spare you all from that overkill. LOL.
Let's get back to dendrites!
cheers,
stephanie :-)
2nd Sep 2012 19:35 UTCStephanie Martin
Dendrites on Feldspar, Ontario, Canada
approximately 6 x 6 cm
2nd Sep 2012 22:57 UTCRoger Curry
just got back from West Cork, Ireland. Went looking for arsenopyrite crystals. Also saw this bit of sandstone, which I left in-situ at the dumps of
Dhurode (Carrigacat) Mine.
Regards,
Rog
7th Sep 2012 05:24 UTCStephanie Martin
Today a little piece of jasper-like material known as opalite from Australia. The information I have says it is found in the opalite mines not far from the Yerilla Chrysoprase Mines in the Goldfield Esperance region, Western Australia.
polished
3 x 2 cm
7th Sep 2012 23:13 UTCRoger Curry
Regards,
Rog
http://upload.wikimedia.org/wikipedia/commons/4/4d/Dendrite_formation.gif
8th Sep 2012 17:18 UTCRob Woodside 🌟 Manager
8th Sep 2012 17:40 UTCStephanie Martin
http://archive.org/details/MSFC-9902621
regards,
stephanie :-)
8th Sep 2012 17:56 UTCRob Woodside 🌟 Manager
8th Sep 2012 18:01 UTCStephanie Martin
8th Sep 2012 20:25 UTCIan Jones Expert
8th Sep 2012 23:10 UTCRoger Curry
Regards,
Rog
http://www.mindat.org/forum.php?addon,11,module=embed_images,file_id=27387
9th Sep 2012 02:47 UTCDan Fountain
9th Sep 2012 10:50 UTCErik Vercammen Expert
9th Sep 2012 13:09 UTCIan Jones Expert
12th Sep 2012 06:56 UTCStephanie Martin
Dan - Those are really wonderful pieces. It would be hard to know which oxide they are without analysis. Both manganese and iron oxides can form dendrites and both be present. You can't always go by colour because some of the managanese oxides can be brown and likely some of the iron oxides could be black.
Ian, thanks for filling the gap and adding a nice dendritic gold specimen. They sure look much like feathers as the sal ammoniac above. The dendritic form is no accident. It appears in many places, not just trees and plants, but also neurons, rivers and as just mentioned, feathers to name a few.
Here are some cabachons with brownish dendrites in agate from Uttar Pradesh, India. When I have time I will add the sizes and perhaps photoshop the background to black to highlight them better.
12th Sep 2012 07:02 UTCStephanie Martin
You can see some brownish "clouds" around some of the dendrite groups.
This is moss agate, while not technically an oxide, it does mimic the dendritic form. These are likely chlorite group inclusions.
12th Sep 2012 19:12 UTCStephanie Martin
cheers,
stephanie :-)
13th Sep 2012 00:20 UTCBradley Plotkin
13th Sep 2012 03:06 UTCRick Dalrymple Expert
More of a true dendrite..
13th Sep 2012 03:10 UTCRick Dalrymple Expert
Thanks Stephanie:-D
13th Sep 2012 05:28 UTCStephanie Martin
In addition to the brown tones you often see dendrites that "bleed blue". This is very typical of the medicine bow agate that I have seen. The secondary colour of course depends on which manganese oxide is to blame.
Medicine Bow agate, Wyoming.
Parral Agate, Mexico
Wave or ripple patterns are noted in this agate.
These dendritic talc slabs from Montana remind me much of "Delft Blue" china. Very distinctive.
16th Sep 2012 21:15 UTCWilliam W. Besse Expert
Actually there are several I saw...
And even MORE...
For those of you that go to the Tucson show you might recognize this as a dealer's warehouse on Main just north of Speedway.
Bill
19th Sep 2012 22:46 UTCRick Dalrymple Expert
22nd Sep 2012 04:01 UTCRick Dalrymple Expert
22nd Sep 2012 20:07 UTCStephanie Martin
Rick, thanks for your latest pics too. The yellow material reminds me of the opalite from Australia.
This week I received a little unexpected bonus. I have a few of these calcites from Ahmednagar, Maharashtra, India, but this one came with a little stow away dendrite inside the longest crystal. None of my other similar calcites from there have any, this particular specimen seems to have a good amount of stubborn matrix attached that appears to be a mix of quartz grains and clay, likely the source for the dendrite. It's not an amazing example but it is very interesting to me coming from this area, I have not seen dendrites on or in any specimens from Maharashtra, an area typically known for zeolites.
Here's the little surprise I found:
whole specimen is approximately 8.x 5.5 cm
I'll be posting more stuff as manage to get the photos done.
23rd Sep 2012 05:18 UTCRick Dalrymple Expert
That is a great find.
Here are a couple of more chalcedony specimens with dendrites.
More to come.
23rd Sep 2012 07:25 UTCAM Mizunaka 🌟 Expert
http://www.mindat.org/forum.php?file,0,file=40710,filename=Dendrite.jpg
25th Sep 2012 06:15 UTCStephanie Martin
In general I've been noticing a lot more bonus dendrites and it can only add to the appeal of the specimen. For example, this material is not the most photogenic, but it is made more interesting by the additional "artwork".
There are dendrites dotted all over the piece, not uncommon for the material and the clay environs, but despite being small this one caught my eye because it seems to have a shadow or a negative mirror image, perhaps a new dendrite forming.
"Me and my shadow".
Dendrites on palygorskite, also known as mountain leather
Velké Hydčice, West Bohemia, Czech Republic
dendrite approx 4mm
27th Sep 2012 05:20 UTCStephanie Martin
The fellow selling them said he "grew" them by dissolving lead in nitric acid and then with the magic of electricity created these forms. So I just had to have them :-D That reminds me, lightning and their by-product fulgurites are also of the dendritic persuasion. I'll have to try and rustle up some good examples of those yet too.
approx 15 mm length
small approx 5mm, larger approx 10mm
27th Sep 2012 09:47 UTCTimothy Greenland
Thank you for starting this!
Here are some shots of paving slabs around my Brother-in-law's garden in the Drôme department of France. I suspect they are of fairly local origin, but can't guarantee that... The black ones are probably manganese oxides and the co-existing ones probably iron. The jointing between slabs is approx 1 inch wide on the average...
27th Sep 2012 11:05 UTCRoger Curry
Electrically grown snowflake. (This has been on my hard-drive for donkeys. Could be copyrighted, I'll attempt to find out where I got it and gain permission or removal) (edit - courtesy of Kenneth G. Libbrecht, www.snowcrystals.com - well worth a visit! Thanks for the URL Cliff)
Artificial fulgurite production youtube
There appears to be two types of dendrite formation, the ordered crystalline type (ice, ammonium chloride etc.) and the chaotic fractal type (manganese oxides, lead etc). However, this I think is only a scale effect, i.e. if a snowflake continued to grow indefinitely, defects would lead to distortions from perfection, until chaos theory would predict an unorganised large scale form such as is shown by manganese dendrites (2D) or flos ferri & fulgurites (3D). Only a guess...
Regards,
Rog
27th Sep 2012 23:12 UTCStephanie Martin
Rog, since you started with a link to the lab created fulgurites, here are some youtube links you might find interesting (if you haven't already seen them) regarding the creation of Lichtenberg figures aka "Captured Lighting" and "Shockfossils". If you needed an idea for a gift paperweight for the exec who has everything, these are rather artful.
The first one is a few minutes long, the second one is about 9 minutes.
After you watch the first one, you can click on the link below it to the shockfossils gallery to see some cool images.
http://www.youtube.com/watch?v=8biE3uP_nOI&feature=related
http://www.youtube.com/watch?v=9Po35g23fYI&feature=related
enjoy,
steph :-)
30th Sep 2012 06:25 UTCRick Dalrymple Expert
30th Sep 2012 06:30 UTCRick Dalrymple Expert
1st Oct 2012 04:07 UTCStephanie Martin
As for the 3D dendrites, I actually have something akin to yours, only the samples I have are in calcite. I was reluctant to post them as the precise locality was not confirmed. The locality information supplied was Ougoud, Morocco, but there is no such match. The closest I could find on google was Tishremt N'Ougoud, in Er Rachidia Province. There are similar sounding towns and I always wonder about translation and the often ambiguous info provided to conceal finds, but with the given information this seems to be the best match possible. It is south east of Goulmina. It is rather timely to post this as the conference for Morocco is coming up soon. Perhaps people will be more on the look out for dendrites in their field trips.
There are 2 samples that appear to have been part of the same geode (?) although the pieces don't match together like puzzle pieces. The dendrites wrap around the pieces like a garland. I wonder if there is any connection to all those quartz geodes with goethite needles?
You can see the 3D impressions in the close up 3rd photo.
4.5 x 3.5 x 3.5 cm and 5.5 x 5 x 3 cm
1st Oct 2012 08:43 UTCDon Windeler
I haven't been taking many photos of late, so I'll have to be content with recycling a shot from my gallery. There are lots of dendritic coppers out there, but this is one of my favorite examples from the collection: a 10.6cm long crystallized piece from the Adventure Mine, Ontonagon County, Michigan.
This piece is flat and looks to have grown in a seam, but whatever it dendritically wormed through is now long gone!
Cheers,
D.
3rd Oct 2012 04:27 UTCStephanie Martin
From copper to a copper mineral, this piece exhibits a row of dendrites sprouting up between the layers. There are also hints and spurts of them between other bands throughout the sample. They do look "3D" but I was thinking that it is perhaps just the luck of the way the piece cleaved naturally Normally they are buffed out and polished removing any traces of depth, so I guess you have to catch them before they get smoothed over otherwise you wouldn't know. I didn't need another piece of malachite but couldn't resist the dendrites on the green canvas.
Malachite with dendrites (probably Congo)
overall size 4 x 2.5 cm approx
5th Oct 2012 06:17 UTCRick Dalrymple Expert
5th Oct 2012 06:41 UTCRick Dalrymple Expert
6th Oct 2012 00:53 UTCRick Dalrymple Expert
This stuff is listed on mindat as jasper from china but it is not a jasper. The slab is so soft that it actually has warped from sitting on a stand. It is now slightly bowed in the center. I would say it is a very soft siltstone or claystone.
I do like the tree-like dendrites.
12th Oct 2012 06:56 UTCStephanie Martin
From Peru
Dendrites, calcite
Some cabachons also from Peru, material is known as Machu Picchu Stone and contains calcite, quartz and the darker red areas are indicated as being caused by the presence of cuprite.
12th Oct 2012 07:03 UTCStephanie Martin
A matched pair of bluish dendritic "landscape" opals
13th Oct 2012 16:29 UTCdaniele ramoino
Thanks to Stephanie and Roger, i just found to have a rock with dendrites,
it come from Maroc desert
Daniele
13th Oct 2012 18:01 UTCJames Pool
There is a very 3d appearance for the dendrites when the slab is wet in water. The largest dendrite is about 1/4 inch or so.
26th Oct 2012 04:51 UTCRick Dalrymple Expert
This is a front and back of the same slab. I just can't decide which is the front and which is the back:-)
It is from a Priday Thunderegg I collected about 12 years ago.
28th Oct 2012 05:51 UTCStephanie Martin
Roger mentioned flos ferri on the previous page, and I have always found these funderful. Here are a couple, and Gail has posted a lovely blue one on the favourites thread if you care to have a peek at that (page 27). I have a little green one but it doesn't have many branches to show the form well.
Aragonite var flos ferri (unforunately some branches were damaged in transport)
Příbram, Central Bohemia Region, Bohemia (Böhmen; Boehmen), Czech Republic
approx 30 x 20 x 20 mm
Aragonite var flos ferri
Bisbee, Arizona, USA
approx 6 x 6 x 5 cm
In addition, cracks and crack formation also fall into dendrite territory. Below is a septarian concretion from Morocco that shows such crack formation that has been filled in by calcite. This is much different than the lovely dendritic concretion section shown by Daniele on the previous page also from Morocco. I hope Daniele finds more of that material to post, it is quite amazing.
Calcite, sedimentary/septarian nodule
Oujda, Morocco
9.5 x 7 cm
30th Oct 2012 15:21 UTCDan Fountain
31st Oct 2012 04:19 UTCMatt Ciranni
31st Oct 2012 06:02 UTCStephanie Martin
:)-D
31st Oct 2012 06:04 UTCStephanie Martin
Thanks for posting. Yes, there is at least one dendrite that I can confirm about half way down on the far right of the specimen, the other dark spots are hard to tell if they are just dirt or a coating of some type, but there could be more dendrites hiding in there.. Mostly these look like quartz stalactites which also do follow dendritic form. Oregon does have some lovely material to contribute!
regards,
stephanie :-)
31st Oct 2012 13:25 UTCRick Dalrymple Expert
Stephanie, I don't get how a septarian is a form of a dendrite?
I do love the flos ferri though:-)
31st Oct 2012 13:33 UTCRick Dalrymple Expert
and one from a mine right around the corner from the...The Baltimore Tunnel, Mercur, Utah
31st Oct 2012 17:03 UTCStephanie Martin
Regarding the septarian, it is not the actual concretion, but rather the crack formations from the weathering process and those have been filled by calcite in the nodule. Cracks are not actually dendrites themselves, however their formations are subject to the same fractal chaos and therefore can be lumped generally under the dendrite umbrella. Hope that helps.
regards,
stephanie :-)
31st Oct 2012 18:48 UTCRick Dalrymple Expert
I think we have a difference in semantics. The internal structure is not a weathering process. It is caused by the internal collapse of the hollow cavity. The hollow cavity is thought to be created when a biological mass, like algae, decay away. Many of the solid ones have other nucleus such as ammonites or other shells. I even have one that I am sure is an algal ball that resembles dinosaur bone. There is a lot of research done on these from Utah. The ones from Morocco have the same genesis. BTW: I have collected the ones here in Utah many times. It is a great field trip and if you are ever in the area, I would be glad to show you around.
As for the fractal pattern (not really chaos as fractals are not random), I couldn't agree more. They are wonderful and that thought adds a whole new dimension to this thread. I am now looking forward to adding a whole new batch of images:-)
3rd Nov 2012 06:00 UTCRick Dalrymple Expert
3rd Nov 2012 10:19 UTCRock Currier Expert
3rd Nov 2012 12:34 UTCPhilip Bluemner Expert
I love dendrites since being a little one. It's so fascinating and fun following the branching growth.
Here's a dendritic fluorite from Moepe Mine, South Africa
http://www.mindat.org/photos/0730057001295076593.jpg
Best regards
Philip
3rd Nov 2012 15:58 UTCGlenn Rhein
About 2-3/4 inches , Most of the Meionite here in Amity has this dendrite coating but this is one of the darker pieces.
3rd Nov 2012 22:41 UTCRick Dalrymple Expert
Glen, Thanks. I love that piece too. My friend collected that about 20 years ago when there was lots in the mine. Now it has been reclaimed:-(
4th Nov 2012 02:07 UTCRick Dalrymple Expert
Here is the septarian I mentioned earlier, with the algal ball in the center. It is from Muddy Creek and was collected last year by a friend.
4th Nov 2012 02:28 UTCRick Dalrymple Expert
4th Nov 2012 03:11 UTCGlenn Rhein
>
> Glen, Thanks. I love that piece too. My friend
> collected that about 20 years ago when there was
> lots in the mine. Now it has been reclaimed:-(
Hey Rick, No mine here in Amity NY just the backyard and some woods. What mine are you refering to ?
4th Nov 2012 03:54 UTCRick Dalrymple Expert
It is from the Tintic Standard Mine (Tintic Standard Mines 2 & 3), East Tintic District, East Tintic Mts, Utah Co., Utah, USA.
It is about 30 minutes from my house. Unfortunately, it has been reclamated recently.
5th Nov 2012 05:43 UTCStephanie Martin
I have a bit of catching up to do so I better get cracking (pun intended)...:-D
stephanie
5th Nov 2012 06:07 UTCStephanie Martin
Rick, that cab IS your own little world... it's cabtastic. Kudos to your son for doing such an outstanding job orienting the stone to full potential.
James - thanks for posting that silver, I will definitely have to look at my sowbelly agate a little closer!
Philip, that is really cool fluorite from an unusual location. That's what I like to see :-D
Glenn, you know I love those! Were you ever able to determine if the dendrites were alanite? In any case that's another lovely specimen.
Getting back to dendrites...
from Kazakhstan
dendritic opal rough
4.5 x 4 x 3 cm approx
agate cabachons
42 x 21 mm and 45 x 17 mm approx
5th Nov 2012 08:58 UTCAntónio Joaquim Monteiro
A.Monteiro
7th Nov 2012 00:21 UTCAlex Homenuke 🌟 Expert
Descloizite dendrites in dolomite(?) surrouded by botryoidal smithsonite, 10cm, Berg Aukas
9th Nov 2012 07:54 UTCStephanie Martin
Antonio - the white dendrites are very unusual and very contrastive, I am curious what mineral they are.
Alex - I don't think I have ever seen descloizite dendrites! Amazing specimen. Glad you found the time to share that treasure.
Here's one from my weird file - a drilled agate pendant, but it has an odd formation of a completely encased bubble inside the agate that has a globular type dendrite forming in it. Unfortunately the agate is too thick and a bit milky so it doesn't allow for a clear focus on the blob, so it will always remain fuzzy, but there is no mistaking it's silhouette. "The Mushroom". The supplier tried to get more information for me on the origin of the material, however the only available information was that the agate location was from China. I am not convinced, but that's all that I could find out. I suspsect it could really be from Indonesia or possibly India. Approx 32 x 22 mm overall.
9th Nov 2012 11:58 UTCRui Nunes 🌟 Expert
Regarding Antonio's dendrites: I have something similar from this mine but not so pretty. I think it's "sugared" barite in a mn oxides environment.
Best wishes
RN
9th Nov 2012 20:47 UTCDan Costian
9th Nov 2012 23:32 UTCDan Costian
Can anybody tell me what can they be? They look like manganese oxide but probably are not.
17th Nov 2012 04:12 UTCRick Dalrymple Expert
I don't know what those dendrites are but they are cool(tu) Why don't you think they are manganese oxides?
Here are some more I came across...
The first one is white dendrite-like feathering in an Oco agate geode. These are common but still beautiful.
17th Nov 2012 04:16 UTCRick Dalrymple Expert
17th Nov 2012 04:31 UTCRick Dalrymple Expert
17th Nov 2012 04:42 UTCRick Dalrymple Expert
17th Nov 2012 05:03 UTCRick Dalrymple Expert
One is green chrysoprase with dendrites from Australia and the other is dendritic opal but I don't know where it is from.
19th Nov 2012 04:26 UTCRick Dalrymple Expert
19th Nov 2012 04:27 UTCRick Dalrymple Expert
19th Nov 2012 06:02 UTCStephanie Martin
Rick, thanks so much for your dedication. Great pieces, I really love the "dandelion" or however you choose to name it. The Hessite was a nice touch also.
I am still having a bit of fun with agates, these come from the same lot as the "Mushroom" above. There seems to be a number of them that suggest images, at least in my overactive imagination.
rose and thorns
celestial body rising on horizon
crooked ghostly smile
19th Nov 2012 16:32 UTCAlex Homenuke 🌟 Expert
19th Nov 2012 19:25 UTCJohn A. Jaszczak Expert
Interesting that the dendrites seem mostly to have simple chemistries. Here is a lovely stellate dendrite of graphite on graphite from the Gouverneur Talc Company mine #4, Harrisville, Lewis Co., New York.
23rd Nov 2012 22:24 UTCDean Allum Expert
Caltech:manganese dendrites
cheers -Dean Allum
23rd Nov 2012 23:33 UTCDan Costian
25th Nov 2012 05:52 UTCStephanie Martin
Dean, thanks for posting the link. Yes was aware of it but didn't think to post it, great that you did.
Dan, I too always wondered about those hollandite stars in quartz, if they qualify as dendrites? There are lots of dendrites that do appear star-like, but these particularly seem to be more acicular than stellate. Will have to look into that more.
Today I am sharing some samples of dendritic uraninite and schoepite from the Ruggles Pegmatite, Grafton, New Hampshire
approx 3 cm
end cut, one side polished
rough unpolished
25th Nov 2012 05:59 UTCStephanie Martin
ex Ben Shaub circa 1930.
Ruggles Pegmatite, Grafton Co, New Hampshire
approx 3.5cm both sides polished
alternate view
25th Nov 2012 13:06 UTCReiner Mielke Expert
25th Nov 2012 17:32 UTCStephanie Martin
regards,
stephanie :-)
25th Nov 2012 17:47 UTCMartin Rich Expert
Nice threat. In the pic below you can see dendrites of Graphite in Granulite. Orning near Melk, Lower Austria, Austria. 9 x 13 cm. Coll. & Photo Martin Rich.
29th Nov 2012 00:11 UTCMartin Rich Expert
The sample I show above has a wrong ID! This an old specimen (1900) from the collection of the Abbey of Melk, Lower Austria I swapt some weeks ago. It was labled as Graphite. After studying a lot of old literature, I´m sure this dendrites are Markasite/Pyrite. The austrian mineralogist MEIXNER analysed this in the 1950´s.
Sorry for the wrong ID.
29th Nov 2012 02:01 UTCDan Costian
Two reasons pro manganese oxides: 1) shape; 2) the bluish diffuse color around which sometimes accompany manganese oxides dendrites.
One reason against: the metallic luster which might indicate some sulfides.
Now, what you show as Tiffany stone does not resemble as such. Google and ebay are full of pictures of that complex mineral which indeed consisted of fluorite (purple in this case), fluorapatite, bertrandite (berylium compound) yellowish and sometimes afghanite.
29th Nov 2012 03:22 UTCRick Dalrymple Expert
I agree they are probably manganese oxides based on color alone.
Tiffany Stone is not a mineral. It is a gem-term for the beryllium ore at (what is not) Wellman Resources. It is composed of bertrandite clay that is impregnated by ground water laden with fluorite, manganese, quartz (agate), and sometimes hylite opal. These have all been confirmed. I have never heard of afghanite being confirmed there but I have only seen one paper on it. The dendrites were confirmed as manganese oxides. The orange and peach colors are also caused by manganese.
There is also small traces of uranium salts that make the agate fluorescent. There is enough of the uranium that when the company was Brush-Wellman, they contaminated the ground water with the waste pile.
I have some more pieces I will try to get photographed tomorrow and post.
Stephanie,
Those uraninite et. al. dendrites are really cool. I have several specimen of that and now I want to polish them. But they are radioactive and the dust... but I want to polish them but they are radioactive... but I really want to polish them:-D What to do:-S
3rd Dec 2012 03:17 UTCStephanie Martin
Rick, your indecision reminds me of Peter Griffin, just before he puts his finger in an electric pencil sharpener. Moral is, don't do it!
This specimen may look like aragonite but it is actually dendritic phillipsite.
Dendritic Phillipsite with some natrolite needles present in vugs
Höwenegg Quarry (Hewenegg Quarry), Immendingen, Hegau, Baden-Württemberg, Germany
79 X 33 X 30mm
3rd Dec 2012 03:25 UTCStephanie Martin
Dendrites on Quartz with Aurichalcite
Stříbrník, Nýznerov, Žulová, Jeseník, Moravia, Czech Republic
60 X 50 X 32mm
3rd Dec 2012 16:06 UTCD Mike Reinke
Have you ever heard of phytoremediation for radioactivity? Sunflower plants clean up radiation. Google it, it's amazing what plants can take out of soil, all kinds of toxins. So plant a area of sunflowers, and do your polishing out in the middle of 'em, just don't breath...
Stephanie, great thread. Never realized they were so cool, and diverse. My first thought was more like ' been there, seen them...' thanks!
3rd Dec 2012 21:13 UTCRick Dalrymple Expert
Thanks for that tip. Maybe they can use the technology to clean up some of the radioactive accidents around the world. Oh, and maybe nuclear power plants should plant them around the reactors in case of a leak;-)
I'll have to read more about this.
All joking aside, this does sound like it has potential. I wonder if it absorbs radon. Along the Wasatch Front, here in Salt Lake City, we have a huge pluton that produces some high levels of radon in peoples basements.
Stephanie,
Another great set of pictures. I hope to get some photography done tomorrow and upload more this week. I found my turquoise with dendrites finally.
3rd Dec 2012 21:48 UTCDan Costian
3rd Dec 2012 23:28 UTCPavel Kartashov Manager
http://www.mindat.org/photo-490360.html
http://www.mindat.org/photo-493849.html
http://www.mindat.org/photo-148567.html
4th Dec 2012 00:18 UTCStephanie Martin
Best Regards,
Stephanie
4th Dec 2012 02:30 UTCPavel Kartashov Manager
Microprobing show absence of cations other than Mn in the mineral. And wet chemical tests prove absence of Mn2+ in it.
Of course, initially these dendrites were formed as manganite or some other Mn hydroxide. But conditions in which the specimen was collected were extremely favourable for dehydratation processes - temperature of black rocks up to 60-70 Co on the sun, air moisture on 5 % level and low atmosphere pressure - heighth ~2000 m over a sea level. In other words, this pyrolusite is secondary.
Look also on not exactly dendritic but all the same very fanciful manganese mineral:
http://www.mindat.org/photo-472200.html
http://www.mindat.org/photo-472203.html
http://www.mindat.org/photo-472192.html
4th Dec 2012 02:49 UTCStephanie Martin
Interesting specimens and I am sure that we will learn more about the unnamed samples in future.
Best Regards,
stephanie :-)
8th Dec 2012 12:48 UTCMatt Wall
I got this nice Kasolite from Shinkolobwe from Leon Hupperichs today, and looking at the back it appears to have some nice dendritic Uraninite. I don't know if Uraninite can occur like this, I assume it does, but I'm not certain. See what you think, (pic attached). :-)
Kind regards,
Matt. :-)
8th Dec 2012 20:50 UTCJohn A. Jaszczak Expert
The second image show close-up images of the stellate dendritic sections taken with a 50× objective lens. (Images taken with an Olmpus PME-3 microscope, Nomarski DIC prism and polarizers, and a Leica EC3 digital camera.)
For more information an images see "Stellate surface features on graphite from Crestmore, California and Amity, New York." Mineral News vol. 28 #11 (2012).
22nd Dec 2012 13:14 UTCRock Currier Expert
30th Dec 2012 04:13 UTCRick Dalrymple Expert
30th Dec 2012 05:07 UTCRock Currier Expert
It looks like no natural turquoise I have ever seen. That's why I suggested that it might not be natural. I may not be correct. We may get lucky and someone may come along here and say, "Yes, I dig that stuff out of my mine all the time and this is the locality." I hope I am wrong.
30th Dec 2012 17:11 UTCRick Dalrymple Expert
Hey, I dug that myself. Really, I collected it at the Color Back Mine in Nevada in 2010. I polished it too. I have uploaded a bunch of specimens from the mine from when I was working with the mine owners and collecting there. Although, looking at the photo I can see why you thought it might not be natural.
If I had to take a guess it is a solid solution of turquoise and variscite, hence the odd color. There must be some silica in the mix as well. It is harder than most turquoise I have cut. This stuff comes in thin seams and when you tap on pieces they sound like glass.
The mine owners call it "blue ice" and they have been trying to market it for a couple of years now but they don't have much. They are asking $800 per pound for it (that is rough cleaned from matrix). I know they have sold several 1 to 5 pound parcels so it should start showing up in jewelry soon. I have about 2 five gallon buckets of rough from the mine and as I polish it I hope to find more dendrites in it.
31st Dec 2012 08:15 UTCRock Currier Expert
31st Dec 2012 15:42 UTCRick Dalrymple Expert
I am not selling it. The mine owners are TRYING to sell it for those prices. They haven't sold much in two years.
I was just saying that I collected some and have polished that piece. I only posted it because of the dendrites.
Mike, one of the mine owners, said it was all studied and identified by the "guys" at the school in Reno. I haven't seen any published papers on it.
1st Jan 2013 09:14 UTCRock Currier Expert
Ask them if the school they are talking about is the school of mines and who were the guys.
1st Jan 2013 16:16 UTCRick Dalrymple Expert
I believe it was somene from the school of mines, but I am not sure. I wont see them again for a few months but when I do I will ask.
1st Jan 2013 21:52 UTCRock Currier Expert
1st Jan 2013 23:00 UTCRick Dalrymple Expert
I completely agree. A name is everything. THat is why they just call it "ice blue" turquoise.
2nd Jan 2013 02:35 UTCStephanie Martin
Rick, that blue ice is surely cool! I am curious to know if it is a mix with variscite as may be suggested and if you can find out for sure.
My current laptop is running on full, so photos have been on hold until I get my new desktop set up shortly. But I have to start the New Year off right so here is a dendrite plate with a wish to all for a happy 2013.
It is rather long and difficult to photgraph well, and it my largest dendrite specimen to date.
Manganese Dendrites
Kagawong, Billings Township,
Manitoulin Island, Ontario, Canada
31 x 9 x 3.5 cm
2nd Jan 2013 15:31 UTCAlex Homenuke 🌟 Expert
3rd Jan 2013 02:36 UTCStephanie Martin
cheers,
stephanie :-)
3rd Jan 2013 08:35 UTCRock Currier Expert
3rd Jan 2013 18:06 UTCBill Cordua 🌟 Manager
3rd Jan 2013 20:26 UTCDon Windeler
Your reminder about including these in the image bank is always a good one; unless it's something off topic or goofy I usually try to post in my gallery first.
I'm curious as to recommendations for the best approach in this particular thread, though. Setting aside the clear-cut examples where the minerals are known, there are a lot of cases of "dendritic Mn-oxide schmutz" where someone probably took a pic more for aesthetics than as a mineral. How best to tag these, especially when this stuff can show up anywhere and usually isn't included in the locality listings?
I may have partly answered myself, though; as I poke around, I see "Manganese oxides" is a catch-all bucket option one could use.
Will try to contribute some of my own soon -- I picked up a few interesting things on the Morocco trip that haven't made it in front of a camera yet.
Cheers,
D.
4th Jan 2013 03:22 UTCGeoff Van Horn Expert
http://img.photobucket.com/albums/v737/airborne200208/0fe54383c60d040f25670c571678c3e1.jpg
5th Jan 2013 09:54 UTCRock Currier Expert
5th Jan 2013 15:51 UTCStephanie Martin
I planned to do an article on dendrites but maybe I will just work on it as a Best Minerals project instead as likely can incorporate much of the information into that format. Thanks for thinking of doing it as a Best Minerals topic.
regards,
stephanie :-)
5th Jan 2013 20:41 UTCRock Currier Expert
6th Jan 2013 00:06 UTCRoger Curry
Regards
Rog
6th Jan 2013 03:07 UTCDon Windeler
So here’s my contribution for the day to the thread, both pictorial and informational. Back in 2008 I was thrilled to purchase this piece, labeled as native copper inclusions in gem chrysocolla from Arizona. (4.8 x 3.0 x 0.6cm, imaged with a cutout of white paper behind it using a Canon photocopier. Will upload to my gallery and include a link here when approved – sorry it’s not a better shot.)
copper dendrites in agate
Not quite, it turns out. Si and Ann Frazier saw the piece at a club meeting and told me the dendrites were artificially added. Apparently there was a gent in Phoenix named Paul Rabbit who’d developed a process to induce copper or tin dendrites in agate, by soaking an agate in a Cu or Sn solution, then putting it in contact with a piece of iron to force precipitation. (I’m oversimplifying, as it apparently took the guy over six years to work out the right way to do it.) He called them “Fischer stones” after Dr. George W. Fischer, who’d self-published a book in 1991 called “Gemstones and chemicals: how to create color and inclusions.”
The source material was “snakeskin” agate from eastern Oregon. According to the Fraziers, this agate is microgranular and has randomly-oriented fibres, which makes it more amenable to the dyeing and dendrite-production process. Since then I’ve bought a Malheur County, OR, nodule of the same from Dana Slaughter, pictured below. (6.5 x 5 x 6.5 cm, also soon to be posted in my gallery.) This picture was taken by Dana and is used with his permission. While not obvious in my picture above, the edges of the polished slice look a lot like the rind on this snakeskin nodule.
Snakeskin agate, Malheur Co., Oregon
The above info on copper dendrites in agate is summarized from a few paragraphs in a Lapidary Journal article the Fraziers had written, cited below. I don’t actually have the article, just the paragraphs Ann sent me, but it sounds like required reading for this thread!
Frazier, Si and Ann (2002). Dendrites: Nature’s Line Drawings. Lapidary Journal 32, 2-02. (sorry, I’m going off an internet search and am not sure on the volume / page numbering...)
Cheers,
D.
6th Jan 2013 10:51 UTCRock Currier Expert
6th Jan 2013 18:34 UTCDon Windeler
I am going to post the pics later today and will link them in when approved -- I just had the inspiration to write down some things after remembering this piece and didn't want to wait around until they were approved to post my comments.
But I sympathize with your frustration at great pics that never make it into the galleries!
Cheers,
D.
7th Jan 2013 03:18 UTCJohn Truax
Interesting thread .... thanks all.
7th Jan 2013 04:55 UTCStephanie Martin
Geoff - that was a happy accident I'm sure (previous page). Nice that you decided to keep the dendrite and share it here. Enjoy it.
Don- great info! And intrigued about those artificially induced dendrites! Your piece reminds me of the copper mineral? dendrites in Dominican Republic pectolite/larimar. I am looking forward to seeing your dendrites from Morocco. One of our club members was at the conference and showed us their trip, and one spot specifically where dendrites littered the ground!
Thanks to all for continuing to contribute to this topic!
regards,
stephanie :-)
8th Jan 2013 05:17 UTCDon Windeler
Cheers,
D.
12th Apr 2013 21:37 UTCRick Dalrymple Expert
Unfortunately, I didn't get to keep this specimen. I only got the hold it for a minutes.
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: March 19, 2024 12:51:20
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: March 19, 2024 12:51:20