Jump to content


Photo

Best Etched Meteorites?

  • Please log in to reply
62 replies to this topic

#26 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 03:52 PM

Kent- I've never bought any etched material from lacroix, just whole Campos, but it looks like very nice work. At around a dollar a gram it would be very difficult to do better. He's apparently buying an enormous amount of material and getting a nice low starting price. Ten years ago whole Gibeons and Muons could be had for less than 20 cents a gram, and that's not very likely these days. The export of Gibeons has been illegal for a number of years, and that's contributed quite a bit to the desireability of Muons.

Lee

#27 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 04:12 PM

I must apologize for my inadequate photographic skills Kent. What appear as black marks are in fact highly reflective and silver colored. They either reflect all the light right back, or in another direction entirely, thus appearing dark. There are a few at the top of the specimen that look silver, the rest are mirror-like as well from the proper angle. Canyon Diablos are a really unique variety to deal with. The appearance can vary from a medium octahedrite (although it's classified as coarse) to an almost featureless gray matte surface after etching. The main mass suffered some really extreme shocking around impact, and this tends to mute or even eliminate the Widmanstatten pattern. In addition there can be a fair amount of carbon in Diablos, often presenting as graphite nodules, which are very desireable to collectors. There can also be an amount of microscopic diamond in the material, either already present before impact, or the formation was exacerbated from the carbon under extreme pressure at impact. These are the most difficult irons I've ever tried to cut, and the only ones that absolutely require a diamond blade.

Lee

#28 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 04:22 PM

This is an unetched 42 gram Canyon Diablo, I left it at a high polish because I just liked the look. There are a couple of bands near the upper edge; if it was etched, these would remain bright.

Attached Files



#29 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 04:31 PM

And finally, a 161 gram Canyon Diablo that looks more like a medium octahedrite. The interesting feature of this one though is how impact stress caused the crystal plates to warp and curve, resulting in a really unique Widmanstatten pattern.

Lee

Attached Files



#30 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 04:56 PM

Lee--I think your photography is beautiful and I remembered looking at your pieces. It must be difficult to get a picture of just the way it looks in person. I really like that high polish one too. The cracks add to the features. I also like that cubed one you have for sale.

#31 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 05:07 PM

Thanks Kent. As when imaging more conventional subjects, I take a lot of exposures and dump most of them. It's certainly an easier task with digital imaging than with film. Just one more pic for now, a 31 gram Mundrabilla. A really unique etch, and a very hard stone. You can see a bit of the crust, it too has a nice reddish patina and is a very stable variety. Seemingly hard to come by these days, their export (Austalia) has been prohibited as well. Lee

Attached Files



#32 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:13 PM

Oh wow. I like that one. I didn't know they were hard to get. It looks like I have one coming from Germany any day now.

Attached Files



#33 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:14 PM

Other side

Attached Files



#34 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:19 PM

Ooops. That is a corner Campo del Cielo of yours that I was looking at. Not a cube. There is a difference. :o

#35 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 05:20 PM

Nice! This is another variety that seems to etch best after bringing the surface to a high polish. There are a number of very good German dealers. One I like alot is Gipometeorites (ebay).

Lee

#36 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:46 PM

Lee-- I just bought that corner piece. I really need to be done buying soon :D. I did tell my wife I was buying several meteorites and she thought I was spending thousands so I do feel better because actually it is just 100's but I think must be going over 1000 easily by now. It is fascinating though.

#37 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:47 PM

I'll have lots of ebay bucks soon so I'll be able to get a small one for free :jump:

#38 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 05:51 PM

I remember looking at Gipometeorites. He does have some nice slices. I bought some from mirko66 and donnersteine.

#39 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 08 September 2013 - 07:41 PM

Yes, Gipometeorites has developed some good sources for his NWA material. I know him personally, although we haven't corresponded in a while. A really nice guy though. Mirko66 I'm familiar with, I think I may have bought from him in the past. Donnersteine is unfamiliar.

Lee

#40 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 08 September 2013 - 07:53 PM

Donnersteine seems to specialize in GEBEL KAMIL

#41 lintonius

lintonius

    Mariner 2

  • -----
  • Posts: 262
  • Joined: 13 Dec 2005
  • Loc: south-central Utah

Posted 08 September 2013 - 09:19 PM

Lintonius; nice Gibeons slices. I can't tell from looking whether ferric chloride or nitol was used. Ferric chloride leaves a higher contrast etch, but individual stones vary in etch appearance, so only a side by side comparison would help. Gibeons tend to have a very tight surface and lack any significant amount of chlorides to begin with, so the ferric chloride method is probably safer here than with the more corrosion prone varities like Campo, Dronino, Nantan, and Muonionalusta. Still, I would personally avoid it, I have a deep seated fear of chlorine contamination.

The way ferric chloride works is a bit indirect. Through a couple of reactions, HCl (hydrochloric acid) is produced, and that is what does the actual etching. It works more rapidly than nitol and produces a darker, deeper etch. Although I've never tried it, I suspect diluting the ferric chloride solution with distilled water would slow the etching process and give you a little more control.

For a discussion of etching techniques, you may consult appendix D of 'The Cambridge Encylopedia of Meteorites' (Norton) or 'The Meteorite and Tektite Collector's Handbook', (Bagnall; Wilmann-Bell).

Lee


Thank you, Lee. Former Michael Casper pieces.
Interesting info too, though I should do some more homework before making any decisions.
I should start by pulling out Norton's CEofM.
Linton

#42 lintonius

lintonius

    Mariner 2

  • -----
  • Posts: 262
  • Joined: 13 Dec 2005
  • Loc: south-central Utah

Posted 08 September 2013 - 09:34 PM

Lintonius- If you want to attempt to re-etch only one face, you can protect the other side with blue painters tape. Butt the seams tightly rather than overlapping, and press the tape firmly onto the surface making sure it's securely adhered at the edges. Sand the surface with 600 grit wet/dry automotive type sandpaper, keeping all the lines straight in one orientation only. The paper fills up quickly, so keep fresh abrasive on the surface. You're trying for a uniform hazy polish. The concentration of your etchant should be such that it takes a couple of minutes for the process to complete, any quicker and it's difficult to control resulting in too dark an etch.

Lee


Yeah Lee. I might try the back first, so I don't lose the etch I already have. I used a random-orbital sander on prior etchings (long-time woodworker;^). I take it you don't recommend that?
Linton

#43 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 09 September 2013 - 12:15 PM

I've actually considered a random-orbital sander (long time woodworker as well), but never actually tried it. I suspect that even the very fine swirls it leaves might be visible in the final etch. I suggested sanding in one direction because the alignment of the crystal plates, especially with fine and medium octahedrites, helps to disguise the visibility of the sanding marks. I finish my pieces first on a stationary belt sander to produce a flat surface, through the sequence of grits, and do the final sanding with a cloth wheel and 'dry' abrasives. Two reasons for this; grit for grit the wheel abrasives do a finer job and leave less distinct lines, and, the cloth wheel will compensate for any surface irregularities and yield a more uniform finish. Of course the foam plate on a random orbital sander might do that as well. I would certainly be interested to hear what kind of results you get.

I got my first large Campos from Michael Casper, a great person to do business with, and a fascinating individual in person.

Lee

#44 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 14 September 2013 - 12:58 AM

Hi Lee:
Does your method of etching give the etch more of a matte look rather than a shiny look. Or is that the difference in types of irons. I really like the look of your Campo del Cielos which don't reflect so much light. Both the Gibeon and Taza etchings I have are quite reflective as if there is a protective coat of something on there. I don't like these as much.

#45 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 14 September 2013 - 03:15 PM

As to any difference between nitol and ferric chloride, I can't say, I've never tried the latter. There may be minor differences between types, but I suspect how the surface is finished prior to etching is more a factor for determining reflectivity. Most of mine are finely ground to 600 grit, so the surface has a matte appearance even before etching. I used to polish everything to a mirror finish, but found it generally unnecessary. The contrast seemed better without polishing, so I left out that step since it's a pretty lengthy process anyway.

Not to say you can't get good results etching a mirrored surface. Since the acid dissolves only the kamacite and leaves the taenite unaffected, that portion ought to remain quite reflective. Some species require a fully polished surface to show a good etch, such as Canyon Diablo and Mundrabilla. Etching these after only a 600 grit finish leaves a muted pattern with poor contrast in my experience.

Some folks do coat their pieces with lacquer or polyurethane. Those should appear uniformly shiney regardless of the viewing angle. Close inspection should reveal if you've got a coated piece. If there is a sprayed on coating, you will be able to slightly dent it with a gently applied fingernail without causing any damage.

Lee

#46 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 14 September 2013 - 03:18 PM

Thanks Lee. Your etching is really beautiful and I can't stop looking at that piece.

#47 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 15 September 2013 - 10:37 AM

I contacted the seller of my Taza and he said there is a clear coating on it. He says he also coats all his irons with Def clear coat. I sure would like to see my Taza without the coating. I guess it must protect it but it is so reflective I don't think it looks as good as it might.

I wonder if Def is a brand or type of clear coat.

#48 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 15 September 2013 - 03:51 PM

I also contacted the seller of my Gibeon and he also coats his irons. "We use a protective coating to protect our meteorites from corrosion. It is a meteorite top coat developed and sold by a company called paleo bond." It is not as reflective as my Taza though. The Taza looks "plasticy."

I just received a 2nd e-mail from the Gibeon seller. "Yes that one had a protective coating put on it called vpci 286 meteorite top coat."

#49 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1267
  • Joined: 08 May 2012

Posted 15 September 2013 - 04:19 PM

I can't believe I just got myself another Taza. I am just disappointed with the plastic one that I have and it is hard to look at. I found this one and immediately liked it. I hope it is not coated the same. Pictures look great I think and it has an inclusion!

Attached Files



#50 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 15 September 2013 - 10:22 PM

I like the Tazas, I think I'll have to keep an eye out for a whole one.

I'm a bit familiar with Paleo Bond through their literature, but have no direct experience with the products. I believe they're highly thought of though.

I came to use gun oil as a protectant after reading an article by Allen Langheinrich (Lang's Fossils and Meteorites) on the care and preparation of irons. It appears in the August 1997 issue of Meteorite!, which I'm pretty sure is out of print.

The use of a clear coating is nice because it enables frequent handling of a specimen. I'm not sure how they hold up over time, I'd certainly be glad to hear from anyone who's had a similarly prepared slice for a number of years. I did at one time coat my pieces, but found even the tiniest bit of trapped moisture became problematic over time, compromising the coating and accelerating corrosion at that point. I like gun oil because it penetrates into any microscopic fissures, and is easily reapplied if necessary. I have quite a few pieces treated with G-96 oil, slices and whole specimens that have remained corrosion free for years, and that is in a fairly humid environment.

Lee






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics