A couple of times a year Jason Phillips of Rocks From Heaven and I will go together on buying meteorites worthy of getting classified. I will cut them in half for our pieces and also remove a piece for the type specimen to send off for lab work. That piece will stay in a collection forever. Well, we are at the end of the whole process now on two stones we sent away a few months ago. So this article is a kind of step by step journey through the process. But here is some general information and etiquette for anyone sending off meteorites for classification.
I suppose the first step is to find a meteorite that is worth the time, energy, and money to have classified. Since I choose to not get generic meteorites done the only ordinary chondrites I send off are ones I guess to be type 3 stones. R chondrites, impact melt meteorites, and other more exotic types I will send those off too. I know it is exciting to get a meteorite classified and have your name appear in the Meteoritical Bulletin Database but some labs are swamped and many just won’t take ordinary chondrites from NWA and other DCAs unless there is something really special going on with them. Of course, if the stone comes from a witnessed fall that happened only days ago there is no problem finding a lab to take it. Or if it is a find with exact location and finder information, they will accept that usually. Some labs are still quite accepting of almost any meteorite if you understand it takes time to get results back. You have to pay for the classification at some places now, so these “cost of work” labs will also accept most any meteorite. Some labs do cost several hundred dollars to do a full classification. To have lunar and martian meteorites done can be even more costly since more work is needed and a second facility with different tools may have to work on a sample. Other labs are less costly but check before you send rocks. Most labs will not return unsolicited materials sent to them so meteorwrongs usually are not returned. Many labs receive thousands of pieces a year of which only maybe one or two samples are actual meteorites.
I took it for granted through most of the last paragraph that the stone to be sent off was an actual meteorite. But that certainly needs to be ascertained if possible before it is sent to the lab for classification. There is going to be a little ranting in this article, not sorry. We work with highly skilled individuals who use expensive equipment both to buy and operate. Also expensive to repair, equipment breaks down and needs to be fixed, calibrated, and replaced. So when you send a rock to a specialist and waste their time because it is a piece of iron concretion or granite it slows the process for everyone else trying to get classifications done.
Along the same lines, some individuals do not accept the verdict they get from scientists that their rock is not a meteorite. They have invested so much hope and thought into it because of the meteorite value reported in the media that when someone unqualified makes a pronouncement that it could be a meteorite their dreams of riches begin. Meteorite scientists are sometimes abused by individuals who simply will not accept being told that their piece of crap terrestrial rock is not made of minerals never seen before. Or their charcoal briquet is not a rare carbonaceous chondrite with diamonds and gold in it. The high school or even college science teacher, unless they have studied meteorites specifically, is not necessarily qualified to identify a stone presented to him. But he may know that saying it is not a meteorite is risky so leaving the submitter with a nebulous answer may seem to be a way of protecting themselves from disputes later. Send the stone you have found to someone who accepts meteorites for examination. Several places can be found online that will look at suspected meteorites for free or a small charge. Then if it is a meteorite choose a lab or the initial examiner may suggest labs. It is sometimes necessary to do a cut or grind a small spot to see the inside to determine if it is a meteorite. That is a thing that often has to happen, sometimes it is unavoidable when fusion crust and other diagnostic features are missing.
But now comes the part many individuals can not do but try to do. The cutting off a nice 20 gram or larger piece of the stone if it is big or 20% if the stone is small. Cutting meteorites needs to be done by people who know how to do it. I see pictures quite often of chunks hacked off stones. Some of these become specimens sent in for classification. We have in the business occasionally bought meteorites that were once fresh beautifully crusted stones that have been hacked on all sides to skin off the fusion crust which was believed to be of more value leaving the meteorite a dodecahedron nightmare. Of course, we paid a tremendously discounted price and had to do some fancy corrective cutting to redeem the material and make money. Rough and ragged cuts are just a shame. The laboratory you choose needs something nice to work with. If it is a natural fragment then that is what it is and there is nothing you can do. But if it is a larger stone then the lab should get something that does not need to be cleaned up to examine it under microscopes or make thin sections from it. Clean up cuts to fix hack jobs use up material that is supposed to be provided for the disposited archival type specimen. The submitter should not send something that will become a bunch of crappy little bits after the lab makes clean up cuts on the piece. And what if something is interesting about the meteorite and the lab asks for a bit more material? More hacking? If you read that as a criticism well you got the message I was trying for. The more people cut off bare minimum weight type specimens with a carbide disk on an angle grinder the more discouraging it will for lab workers. Lab time is expensive and if they send out for their thin sections then 6 weeks or more may already be part of the time for the classification. Spending valuable time preparing a surface to cut thin sections off is a waste of time and material. Send your meteorite to someone to have it professionally cut to produce the type specimen. Have a couple more pieces cut off if you want for yourself and have the main mass polished perfectly flat and smooth on equipment made for the work. Not a lapidary drum grinding wheel so it has nice rounded off edges using tap water coolant with additives and messy polishing compounds. Meteorites should not be included with regular lapidary thinking. More ranting I know but, we are dealing with rare material that comes from outer space and it needs to not fall apart in a year or two because it was cut wrong and prepared wrong. Regardless of how nice it may look immediately, time will always tell and the archived pieces sent to labs are supposed to last forever and come to them uncontaminated.
Many labs ask for payment to do classifications. Some will accept donations of genuine meteorite material in place of cash. Find out which the lab wants. If it is meteorite material be generous if you can. This material is often used by students to learn on. They will be the scientists and classifiers of the future. A mistake I sometimes make is to not include the same amount of information on the donation material as I do with the type specimen pieces. The donations will often become part of the permanent collection as well, so the location and finder or circumstances of the purchase are all important data. As is the total weight of the piece the donation comes off of.
After all that is done and you have mailed off your specimen of confirmed meteorite material or at least highly suspected meteorite material it is time to wait for the lab to do its work. If it turns out it was close but still a meteorwrong then you will hear that news pretty fast. It will be eliminated during the first few looks. Your real meteorite submission will proceed through all the necessary steps of analysis, but you are at the end of a long line usually, many meteorites in front of yours. The process can take months often and longer occasionally. There are meteorites still not finished and official that individuals submitted years ago to some labs. The reason some are never official is the lack of data about the find and finder. Make sure from the beginning that you know the names, places, and dates of the events involved with the stone. Also, you need to know the exact weight of the stone and if applicable the number of pieces or fragments found.
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So that was a preface to the actual process that Jason and I have been enjoying for the last few months. I say enjoying it because we do this for fun as much as to make our small contributions to science. If we did not do these meteorites during the year we would talk, email, and message far less and likely only have our time at the Tucson Gem Show to catch up on family and life. But we email back and forth over the year and talk about other things along with the results slowly coming to us about the meteorites.
In the early spring of 2019, Jason emailed me that a friend across the vast Atlantic Ocean had a couple of meteorites that were exciting looking. He asked if I was interested in going half and half with him. I thought about it and saw one or two pictures and pretty fast said “sure.” So the meteorites arrived at Jason’s and he forwarded them to me. I received them of course or we would not be having this for an article. I took some images and got the weight of the stones uncut for the meteorite submission later. I marked the stone I am discussing to maximize the fusion crust for both of our halves. I put the stone across a straight edge and balanced it to find the place to cut and chalk marked it as shown in the image below. I adjusted the place to cut a bit so one piece was heavier to cut the type specimen off and still leave us equal weights or nearly so.
I mounted the stone in my saw. I have featured the saw on FB and articles here in Meteorite Times previously. It is a saw I designed and made for just doing meteorites and other valuable stones. It uses extremely thin blades. It works only for stones that are not too big. I can do meteorites up to about 1.5 kg. More than that weight and they go on another of my saws. I did sneak a 1.6 kg lunar on the saw a couple of years back that was exciting and great fun.
I did the first cut and then took the cut for the type specimen. I lapped all the surfaces through the grits of diamond disks to 1200 and then polished all the surfaces with 100K mesh diamond. I photographed and weighed the halves and type specimen. I sent Jason his half. I knew he was as excited as I before mailing it. I was sending Jason images all along during the prep work. After the first cut, I just about fainted when I saw all the chondrules and the elongation and possible orientation of the chondrules. This was a special stone even though it was likely a type 3 chondrite. We were confident it was a type 3 before we bought it. There was plenty of evidence on the outside of the stone. Chondrules were exposed in several places and their sharply defined edges and abundance seemed good evidence of petrologic type 3. The lack of anything looking like carbonaceous made ordinary chondrite a good possibility. Once it was cut the visible metal and chondrule average size moved the possibility of LL into the running.
I put together a donation for the lab of mixed classified and unclassified meteorites after asking about what they would like from what I had. I wrote up a letter including all the information that I knew at the time for the two meteorites we were sending to be classified. The other meteorite went through a similar procedure of imaging, weighing, marking, cutting, and preparation. A type specimen of it was being sent too. It looked less like a type 3 and very different but we had hopes since Jason and me are both petrologic type 3 lovers. Off into the mail, it all went with insurance. I heard in a few days that it had arrived and been opened. The words “looks fantastic” were said of the one we are discussing now. The elongated and possibly oriented chondrules were of particular interest to one of the researchers at the lab and a request for another piece was made. I put my half back in the saw and make an additional cut. I cut right through the middle of one of the large chondrules at right angles to the face on my half. The result was a very elongated bean-shaped chondrule was more fully exposed. The additional 9-gram small end cut was set off to the lab.
Now the waiting began. I got some quick initial information but more information would be the normal length of time away. When the data began to come in it was exciting. The meteorite had several interesting characteristics besides the squeezed and elongated chondrules there was zoning in the olivines and more. I was thrilled to read the messages every time I got a little update. They would often come with images from the equipment. Not that I understand much about Back Scatter Electron analysis it was great to receive the images.
This is a montage of BSE images from the analysis. As it turns out the thin section used for some of the work was taken from the small additional end cut that I made. At the same time that the BSE image was sent an image of a thin section in a visual microscope was received. This one I did understand after all my thin section making and photography. My reaction was WOW! There was such chondrule density. There were deformations of chondrules in areas. This had indicated a cluster chondrule texture in a previous meteorite I had classified (NWA 11991). So now I look for chondrules that are dented and packed against each other in a deformed sort of jigsaw puzzle texture.
During the months of waiting to hear results, I had the half stone to enjoy. It sat right above my desk workspace on the top of my secretariate with many others, also mugs and a clock or two. I have some hobby mixing going on up there. But I pulled it down and looked at it many times. Always amazed at what I saw. So here are a few images of the stone.
As I wrote earlier there was only a bit more than one side with preserved nice fusion crust. The remainder of the exterior was sandblasted clean. The fusion crust that was there was fresh and black. Jason and I expected that the stone was going to be fresh when it was cut since there was no brown rusty color on the exterior at all. We were not disappointed, the matrix is gray and fresh and there is no discoloration around metal grains and no missing metal to weathering. So we were expecting a lower weathering grade. I saw no strong shock features like shock veins or bad shattering of chondrule grains so was expecting a low or moderate shock grade also. It is fun to guess but you just have to wait and hear what the real experts tell you when they are done working.
Note the fine surface details preserved as tiny bumps in the fusion crust and also the contraction cracks. The surface has thumbprints all over but they are especially nice and seen best on the fusion crusted areas.
The fusion crust does run over the edges of the one side and here is a view of the partially crusted end and a sample of the exposed chondrules seen on the wind-eroded portions of the stone.
Another area of the exterior with the chondrules showing is seen here. It was not difficult from seeing images like this to know that this was going to be an interesting stone when cut.
Above is shown the cut and polished face of my half of the stone. Jason’s half had a large inclusion or huge chondrule that was kidney bean size and shape. The stone has some troilite inclusions and scattered metal but the metal it has is in smaller-sized irregular shaped clumps indicating again to this amateur that LL was a possible type. L type chondrites ofter have few but larger clumps of metal. The following images are closer views of the surface.
This first close up image shows what I thought was clustered chondrule texture. The chondrules are not nice and round in areas. They are dented by the chondrules pressed against them. There is almost no fine grain matrix between the chondrules in many places. But clustered chondrule texture was not mentioned by the classifiers in the final writeup so I still have something to learn about clustered chondrules. The one slightly larger chondrule with the white border shows the denting very well. The white border has a dent in the 6 o’clock position. Many chondrules are surrounded by thin rims of sulfides. The brown mass upper middle is a troilite inclusion with an irregular shape there is another bottom center edge that is nicely round and globular. This is a fairly high magnification image but the next one is even a closer image.
The dark black spots in this image are tiny grains of nickel-iron not reflecting any light. The two spots in the upper right corner with the horizontal lines are also metal with regrettably a few residual streaks from fine lapping. The entire field of view seen in this image is about 1.0 x 1.3 cm.
Near the very end of the classification work, I received some element map images. I do not have much to say about them other than what was in the communication I received. I am not very knowledgeable about this analysis data. But I offer to you the images for your enjoyment and edification. There was a set of six images. The first offered here is an area map of the portion under analysis.
There were five element maps in the set I am only going to offer one image. The chondrule under analysis has separation of Na, K, Ca feldspathic material and this is the K-Ca-Na map. The field of view in the element map is roughly 600 microns or a bit more determined from my measurements of the scale I cropped from the bottom of the images.
The following image shows what the classifier called “something trying hard to be a barred olivine chondrule.” The meteorite she said has “some gorgeous strongly zoned olivine.” Which can be seen in this image.
When the analysis process was all finished write-ups about the meteorites were prepared and sent to the Nomenclature Committee of the Meteoritical Society. Acceptance by the committee will result in the meteorites becoming official and having a place in the Meteoritical Bulletin Database with a name or number designation. If the meteorites are ever interesting to a researcher then the type specimen’s location is recorded in the database entry. As I finished writing the article I received a message that the write up was done and submitted so I will include it here. Weights, find location, main mass holders and all other such information, like the number of pieces and find or purchase details are in a different area of the final listing and do not show here.
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Class: Ordinary chondrite (LL3)
Shock: S3
Weathering: W1
Fa: 25.3±9.0 (N=157)
Fs: 12.8±9.5 (N=33)
Wo: 0.9±0.8 (N=33)
Physical characteristics: Cascadia received an end cut and a small corner piece; exterior surfaces of both are abraded, dark gray, and bumpy, with lighter-colored chondrules visible. The cut face shows well-defined, oblate, and aligned chondrules set against a medium gray background. Sulfide and metal are visible, mainly rimming chondrules. Two perpendicular faces are visible on the corner piece; chondrules are oblate and aligned on only one face.
Petrography: (M. Hutson and A. Ruzicka, Cascadia): Chondrules are distinct, and have an apparent mean diameter of 0.99±0.46 mm (N= 36). Many chondrules are surrounded by rims of mainly sulfide. Fe-Ni metal comprises 2.1% of the thin section. Native copper is present. Visible in thin section are brown glass, low-Calcium clinopyroxene, and zoned olivine grains, as well as “bleached” rims on some chondrules. BSE imaging shows many examples of forsteritic olivine cut by linear bands of Fe-rich olivine that appear to represent pre-terrestrial alteration along fractures.
Classification: Ordinary chondrite (LL3) based on olivine fayalite content, metal abundance, and mean chondrule diameter.
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I love reading things like “native copper is present” it sends me back into my personal lab and photo studio to examine the polished face at an angle that will show the metal brightly. Just to see if I can find any of that copper.
I would like to take this opportunity to thank Dr. Melinda Hutson and Dr. Alex Ruzicka, Dick Pugh and all the staff at Cascadia Meteorite Laboratory for the work that they do for me and all the meteorite community. They are tireless in their efforts to do the best possible science with the space rocks we send into them. I have no words to offer which can fully express the excitement I feel as the results come in on submitted specimens. It comes close to the feeling of finding and holding a meteorite for the first time in the field. Hearing the results is often the high point of a whole week, thank you, guys.
Addendum
Just a couple days before this issue of Meteorite Times was published I received the word that both the meteorites had been approved and had their number designations. The meteorite I have featured in this article is officially NWA 13090.
