I may have found a couple of meteorites

[Ivan Seeking]

Because our creek moves a great deal of rock, I've been meaning to work it with a metal detector during the summer months when it's dry, for a long time now. It seems likely that a meteorite would get deposited on the property during heavy flows, from time to time. A friend finally loaned me his detector so I gave it a go. Within an hour I found three possible candidates, with one quickly ruled out as it's not affected by a magnet. The other two are looking somewhat promsing. I've been reviewing the various tests that one can do at home, but suggestions are appreciated.

I've done rub tests and visually inspected them to see if they could be magnetite or hematite. So far they seem to look more like iron meteorites than anything else. I just tried using a file on one surface of each and put them in vinegar. I don't know if the low concentration of acid will be enough to work with time, but I know from previous reading that stronger HCL will leave a dististinctive cross-hatch pattern in some types of meteorites, so I'm hoping vinegar might be enough if left to soak long enough. If not, perhaps muriatic acid will work? I haven't spotted the required concentration yet. Maybe I'll need to get something stronger?

I started with this site as a reference.
http://static.arxiv.org/pdf/1109.4897.pdf

One find is just a pebble really; pyramidal in shape with about a 0.5 x 0.5 inch base. The other candiate is more like 1" x 2" x 0.75" in size.

 

[Evo]

That is so cool, I hope they are meteorites!

 

[zoobyshoe]

"Muriatic" is another name for hydrochloric acid.

I buy it by the gallon as a cheaper and better version of CLR (Calcium-Lime-Rust remover). It's sold by the gallon for killing bacteria in swimming pools.

I've played around putting nails and pieces of aluminum in it, and it starts to attack them pretty readily. It gives off hydrogen gas, and the acid starts to become to a chloride of the metal.

The stuff sold for swimming pools is already dilute. If that's what you have, practice on nails to see how long to leave it in before the surface oxidation is removed. That may only take 5 seconds or so, depending on the nail. The generation of hydrogen gas will be immediate and completely apparent.

On the other hand, vinegar can be turned into very weak hydrochloric acid just by adding common table salt. This will require a lot longer "soak". You will barely be able to see any gas bubbles forming. That may be the safer way, though.

 

[Ivan Seeking]

"Muriatic" is another name for hydrochloric acid.

I buy it by the gallon as a cheaper and better version of CLR (Calcium-Lime-Rust remover). It's sold by the gallon for killing bacteria in swimming pools.

I've played around putting nails and pieces of aluminum in it, and it starts to attack them pretty readily. It gives off hydrogen gas, and the acid starts to become to a chloride of the metal.

Yes, I knew that Muriatic acid is just the commercial name for relatively dilute HCL, but you make a good point. I too played with muriatic acid and aluminum foil [a long time ago] and it did react readily and strongly for an off-the-shelf home product. That should be enough for the test that I've seen done. I can use the rest to clean my driveway.

On the other hand, vinegar can be turned into very weak hydrochloric acid just by adding common table salt.

I don't think I've ever heard this. I'd have to go back to my college chem book.. I guess that makes sense... but instead will take your word for it. With time, even a very dilute solution would work, I would think.

 

[Ivan Seeking]

Whoops, the link I provided earlier may not be the best source for identifying meteorites. This is the link I meant to post.
http://epswww.unm.edu/iom/ident/index.html

Both rocks appear to have a fusion crust, and both are very dense. Also, the rock that produced the hit but failed the magnet test, does not have the dark crust. I went to check the density but my old triple-beam took a hit somewhere along the line and I didn't know it. I'll have to fix that before I can check.

Also, I incorrectly said it looks like an iron meteorite. I should have said stony meteorite.

 

[zoobyshoe]

I don't think I've ever heard this. I'd have to go back to my college chem book.. I guess that makes sense... but instead will take your word for it. With time, even a very dilute solution would work, I would think.

I don't know the chemistry behind it, but it's the old "clean the copper" technique you find in lists like "How To Clean Anything!"

Also in chemistry demonstrations for kids:

Salt, or sodium chloride, combines with acetic acid from the vinegar to produce sodium acetate and hydrogen chloride. Hydrogen chloride is a strong acid and the combination of it and sodium acetate rapidly cleans the surface of the penny (most pennies are 95% copper, 3% zinc, and 2% tin on their surface). The cleaning process leaves a very pure metal surface which quickly corrodes when exposed to the water, oxygen, and carbon dioxide from the air. Can you now explain why the copper domes often seen on buildings appear greenish?

http://www.chem.umn.edu/outreach/card-saltvincopper.html

It's HCl, so it also interacts with other metals, of course.

 

[zoobyshoe]

Whoops, the link I provided earlier may not be the best source for identifying meteorites. This is the link I meant to post.
http://epswww.unm.edu/iom/ident/index.html

Both rocks appear to have a fusion crust, and both are very dense. Also, the rock that produced the hit but failed the magnet test, does not have the dark crust. I went to check the density but my old triple-beam took a hit somewhere along the line and I didn't know it. I'll have to fix that before I can check.

Also, I incorrectly said it looks like an iron meteorite. I should have said stony meteorite.

Did you try the "streak" test?

Streak
Streak is what the rock leaves behind, like a crayon. Common ceramic tile, such as a bathroom or kitchen tile, has a smooth glazed slide and an unfinished dull side which is stuck to the wall when installed. Take the sample that you think is a meteorite and scratch it vigorously on the unglazed side of the tile. If it leaves a black gray streak the sample is almost certainly magnetite, and if it leaves a red-brown streak it is almost certainly hematite. A meteorite, unless it is very heavily weathered, will not leave a streak on the tile. If you don't have a ceramic tile, you can also use the inside of your toilet tank cover (the heavy rectangular lid on top of the tank) - it is heavy, so be careful.

 

[DaveC426913]

Cool.

Every once in a while, when I come across a farmer's field with a stone wall, I try to examine it for possible meteorites. It works well in England, where there are miles and miles of stone walls, from centuries of farmers clearing their fields of stray rocks. (A trick I learned from a Paleo/Geology girlfriend many lifetimes ago)

 

[Ivan Seeking]

Did you try the "streak" test?

Yes I did, but the first time I tried it on somewhat coarse cement and saw nothing. Last night I decided to take the suggestion from the page and tried it on the inside of the toilet lid. This time there was a distinctive gray streak. This suggests that it's magnetite. But the streaks were light gray, not dark gray, so I'm going to hold out for the density test before calling it a wash. At this point, unfortunately, I would have to say they are likely magnetite.

I thought I had already ruled out magnetite with another test... I need to back and review the web pages. Maybe it was the first streak test that I had in mind.

 

[zoobyshoe]

Yes I did, but the first time I tried it on somewhat coarse cement and saw nothing. Last night I decided to take the suggestion from the page and tried it on the inside of the toilet lid. This time there was a distinctive gray streak. This suggests that it's magnetite. But the streaks were light gray, not dark gray, so I'm going to hold out for the density test before calling it a wash. At this point, unfortunately, I would have to say they are likely magnetite.

I thought I had already ruled out magnetite with another test... I need to back and review the web pages. Maybe it was the first streak test that I had in mind.

See if the suspected magnetite is, itself, magnetic. Will it attract small bits of steel/iron?

 

[zoobyshoe]

Regardless, I wouldn't give up with the metal detector.

I got a cheap one, myself, at the swap meet years ago and determined to go down to Pacific Beach early in the morning. When I got there I found twenty other people with metal detectors.

You, on the other hand, have "virgin" territory to explore, and you never know what you might find.

 

[Ivan Seeking]

See if the suspected magnetite is, itself, magnetic. Will it attract small bits of steel/iron?

No, it is not magnetized, but I couldn't remember if this is definitive for ruling out magnetite.

 

[Ivan Seeking]

Regardless, I wouldn't give up with the metal detector.

I got a cheap one, myself, at the swap meet years ago and determined to go down to Pacific Beach early in the morning. When I got there I found twenty other people with metal detectors.

You, on the other hand, have "virgin" territory to explore, and you never know what you might find.

No doubt, I'm really into virgin territories. :tongue2:

Seriously though, I've seen what this creek can do when we have a lot of rain. It can trench down six feet into hardpan in a few hours, and move rocks over 80 lbs. After we had a 500 year flood, I found one ~ 500 Lbs tree stump in my pasture! So it's like a little time machine feeding from the hills above and beyond us. That's what motivated me to start looking. And beyond meteorites, gold is another likely find. We have tons of quarts coming in and on our own property - we have collected buckets full of that, tourmaline, agate and other interesting and semi-precious stones. The creek also has lots of black sand, and even blue water at times, both of which can indicate the prsesence of gold.

 

[zoobyshoe]

No doubt, I'm really into virgin territories. :tongue2:

Seriously though, I've seen what this creek can do when we have a lot of rain. It can trench down six feet into hardpan in a few hours, and move rocks over 80 lbs. After we had a 500 year flood, I found one ~ 500 Lbs tree stump in my pasture! So it's like a little time machine feeding from the hills above and beyond us. That's what motivated me to start looking. And beyond meteorites, gold is another likely find. We have tons of quarts coming in and on our own property - we have collected buckets full of that, tourmaline, agate and other interesting and semi-precious stones. The creek also has lots of black sand, and even blue water at times, both of which can indicate the prsesence of gold.

I meant to go gold panning up in Julian all summer, but never made it. Anyway, there are a few dozen youtubes on how to pan. It's also a good idea to learn how to recognize a diamond because people are said to find them occasionally when gold panning. As you said, things can get moved very far from their source. There is a known huge diamond field in Canada.

 

[Ivan Seeking]

I meant to go gold panning up in Julian all summer, but never made it. Anyway, there are a few dozen youtubes on how to pan. It's also a good idea to learn how to recognize a diamond because people are said to find them occasionally when gold panning. As you said, things can get moved very far from their source. There is a known huge diamond field in Canada.

This area was heavily affected by the Great Missoula floods. So deposits coming directly from as far as Montana, can be found here. Even today one can find huge boulders still standing in the middle of grasslands and farmland, where they were deposted over 10,000 years ago.

 

[zoobyshoe]

This area was heavily affected by the Great Missoula floods. So deposits coming directly from as far as Montana, can be found here. Even today one can find huge boulders still standing in the middle of grasslands and farmland, where they were deposted over 10,000 years ago.

So, considering that, and all the quartz, it is well within the realm of possibility that you might find gold dust, even nuggets. No telling what you might find.

 

[Ivan Seeking]

For years I was collecting the pieces to an old truck - last registered in 1938...or was it 48? old in any case - one part at a time. One year I found a license plate, then a leaf spring, and I think a steering arm. For the next ten years or so I continued to find a piece here and a piece there when we'd walk the creek each summer. The joke was that, eventually, I'm going to rebuild that truck!

I actually have both license plates, so I'd even be legal.

I was thinking it was from the 30s, but now, 1956 comes to mind. I'll have to look again.

 

[Ivan Seeking]

Okay, self-magnetized is definitive for magnetite, but not necessary. However, interestingly, in all the photos that I've seen, the magnetite is much darker and rounder, and more porous than this piece. So far I haven't seen any examples that look the same. It is described as black. I certainly wouldn't call my sample black. At most, dark gray. After filing on the small piece, it was clear that the material under the crust was a much lighter gray color.

Hopefully I can get my scale fixed tomorrow.

 

[zoobyshoe]

For years I was collecting the pieces to an old truck - last registered in 1938...or was it 48? old in any case - one part at a time. One year I found a license plate, then a leaf spring, and I think a steering arm. For the next ten years or so I continued to find a piece here and a piece there when we'd walk the creek each summer. The joke was that, eventually, I'm going to rebuild that truck!

That'd be funny.

Okay, self-magnetized is definitive for magnetite, but not necessary. However, interestingly, in all the photos that I've seen, the magnetite is much darker and rounder, and more porous than this piece. So far I haven't seen any examples that look the same. It is described as black. I certainly wouldn't call my sample black. At most, dark gray. After filing on the small piece, it was clear that the material under the crust was a much lighter gray color.

Hopefully I can get my scale fixed tomorrow.

Might be a hunk of cast iron. If you have any cast iron implements in your kitchen you might take some sandpaper to the bottom of one till you get down to the uncoated metal, which, you'll see, is actually a medium grey with very distinctive grains visible. I had to machine some cast iron once. It doesn't form a "chip" like steel, but comes off in granulated form, and the newly exposed surface is much lighter in color than I suspected.

Now, I'm also wondering what the sample was that set off the metal detector but wasn't attracted to the magnet. Brass? Copper? Platinum?

 

[Ivan Seeking]

Might be a hunk of cast iron.

I seriously doubt that. It certainly appears to be a stone of some kind. I'll post some pics later when I have more time [gotta get back to work now].

Now, I'm also wondering what the sample was that set off the metal detector but wasn't attracted to the magnet. Brass? Copper? Platinum?

I'll include that one in the photos. Also, by tonight I may have had a chance to fix the scale and get a density measurement.

 

[ArcanaNoir]

Last night I decided to take the suggestion from the page and tried it on the inside of the toilet lid. This time there was a distinctive gray streak. This suggests that it's magnetite.

Ew! Lol. Now that's using what you have on hand.

 

[turbo]

If you know someone who cuts gemstones, you might be able to get them to machine and polish a flats in the rocks. If you want to check the stones with acid-etching, you'll need those flat polished surfaces to bring out the structure.

 

[Ivan Seeking]

It looks like the old triple-beam is a lost cause - I think the frame has been tweeked - so I'll have to arrange something else. In the mean time, I did take a few photos. The graph paper is 0.25" ruled

Stone #1: You can see the flat section that I filed. Note that some photos are a bit out of focus as I was pushing the limit of the camera, but they still show the shape and color pretty well.

http://img706.imageshack.us/img706/7178/m1ay.jpg

http://img854.imageshack.us/img854/395/m1b.jpg

Suspended from a strong magnet.

http://img819.imageshack.us/img819/1801/m1czl.jpg

http://img825.imageshack.us/img825/2778/m1d.jpg

Stone #2: A small pebble, I filed the bottom and exposed the gray material beneath the crust.


http://img838.imageshack.us/img838/596/m2ak.jpg

http://img535.imageshack.us/img535/8617/m2bx.jpg

Stone #3: This one is not affected by a strong magnet but tripped the metal detector. Obviously it's not a meteorite. It seems to be clay or sandstone with a dark material embedded in it. Presumably that's what tripped the detector.

http://img703.imageshack.us/img703/1056/m3aa.jpg

 

[zoobyshoe]

Is the presumed metal in the third sample soft enough to be gouged with a nail, or is it hard?

 

[Ivan Seeking]

Is the presumed metal in the third sample soft enough to be gouged with a nail, or is it hard?

It just scrapes away with sandstone or clay below. Why are you so interested in the third one? That surely isn't a candidate for anything interesting.

I just ordered a new scale.

 

[zoobyshoe]

It just scrapes away with sandstone or clay below. Why are you so interested in the third one? That surely isn't a candidate for anything interesting.

It's native metal of some sort, that is not iron. That interests me. All kinds of metals might be found in sandstone. Gold, copper, silver, platinum metals, uranium, to name some I've read mentioned. It might be something boring like lead or tin, but it might not.

 

[DaveC426913]

Ever though of doing any panning for gold in that stream of yours?

 

[physics girl phd]

Yes I did, but the first time I tried it on somewhat coarse cement and saw nothing. Last night I decided to take the suggestion from the page and tried it on the inside of the toilet lid. This time there was a distinctive gray streak. This suggests that it's magnetite. But the streaks were light gray, not dark gray, so I'm going to hold out for the density test before calling it a wash. At this point, unfortunately, I would have to say they are likely magnetite.

Is there anyone else that finds a streak-test on a toilet a bit disturbing?

I guess this relates to my loss of interest in a lot of geology... in 8th grade science, my teacher passed around rock and mineral samples and encouraged students to taste the salt chunk (about the size of a small child's fists. Well, JoJo P (the student sitting next to me) plopped the whole thing in his mouth and slurped on it for a good long while before slopping it back on the tray (covered with his saliva) and passing it to me.

I'm recovering interest, albiet slowly (and thank goodness I guess in that I had a fair amount of pre-knowledge going into 8th grade that didn't get cleared by the experience). Not sure streaks on a toilet helps here though...

 

[Ivan Seeking]

Is there anyone else that finds a streak-test on a toilet a bit disturbing?

At least they don't call it a skid test; where you check for skid marks!

Apparently the streak test is a standard technique, and the inside of the tank lid is just the right type of surface and ceramic. Given that toilet tank water is considered an emergency supply of drinking water, it's not THAT bad.

Dave, I've had a guy pushing me to work this creek for gold, for years. He offered to do the work for half the take, assuming there is any. That sounded pretty good to me. Last time he was here he took a bucket of black sand to sift for traces. So far I haven't heard anything.

 

[FlexGunship]

The joke was that, eventually, I'm going to rebuild that truck!

Every time I rebuild a carburateur I seem to have pieces left over. I figure it I do it enough times, I'll finally just have two carburatuers.

Given that toilet tank water is considered an emergency supply of drinking water, it's not THAT bad.

Yeah... but, I mean... it's not just for emergencies. Right?

 

[FlexGunship]

Like an idiot, I totally missed those pictures before! That's crazy, I have a rock I tucked away from when I went hiking in Vermont. I took it because I specifically remember thinking it looked like a meteorite. It looks a lot like your's Ivan. No joke. It, too, was magnetic, but that's as far as I got.

Time to check closets. We can compare notes.

 

[zoobyshoe]

See here, there are four known platinum deposits in Oregon:

http://www.mindat.org/min-3236.html#themap

A lot more in Northern California.

 

[Borek]

On the other hand, vinegar can be turned into very weak hydrochloric acid just by adding common table salt.

I wouldn't say so. Yes, you will have both H⁺ and Cl^- in the solution, but calling it hydrochloric acid is wrong.

There are two important properties of hydrochloric acid - it is strong (that is, its is almost 100% dissociated and its solutions contain a lot of freely available H⁺) and it contains plenty of Cl^- (important when dissolving metals easily complexed by chloride ions - iron included). Solution of NaCl in vinegar will contain a lot of Cl^-, but concentration of H⁺ will be just that of acetic acid. It will not behave like hydrochloric acid.

 

[zoobyshoe]

I wouldn't say so. Yes, you will have both H⁺ and Cl^- in the solution, but calling it hydrochloric acid is wrong.

There are two important properties of hydrochloric acid - it is strong (that is, its is almost 100% dissociated and its solutions contain a lot of freely available H⁺) and it contains plenty of Cl^- (important when dissolving metals easily complexed by chloride ions - iron included). Solution of NaCl in vinegar will contain a lot of Cl^-, but concentration of H⁺ will be just that of acetic acid. It will not behave like hydrochloric acid.

I believe you, and am not really surprised popular explanations would end up calling it by a misnomer. I suppose the important questions are 1.) will it dissolve (or "etch") metal in the way Ivan wants, and 2.) what should I call it if I ever refer to it again?

 

[Ivan Seeking]

I guess this relates to my loss of interest in a lot of geology... in 8th grade science, my teacher passed around rock and mineral samples and encouraged students to taste the salt chunk (about the size of a small child's fists. Well, JoJo P (the student sitting next to me) plopped the whole thing in his mouth and slurped on it for a good long while before slopping it back on the tray (covered with his saliva) and passing it to me.

This reminded me of something I saw on The Naked Archeologist. He did a show on ancient artifacts from the Middle East. Fake artifacts are big business and it's easy for tourists to get duped. In conjunction with a noted collector, the narrator/scientist explained that one can easily check for age by doing a taste test. If something is truly old, it will taste salty. I mentioned this to the owner of PF when he went to Egypt but he didn't seem too interested. Maybe he didn't want to go to a Egyptian jail for licking artifacts in public...?