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.

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.

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...?

 

[Ivan Seeking]

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.

Which apparently answers the question of whether sodium acetate is soluable in HCL. I thought it might form a precipitate.

 

[Borek]

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?

1. I doubt. Too weak acid.

2. Just a mixture of acetic acid and NaCl.

There are cases when such mixtures have properties different than just a sum of components, two most obvious cases I can think of are Aqua Regia and fluorides dissolved in hydrochloric acid. But in both cases there is some additional chemistry involved, there is no such thing in the acetate/HCl mix.

Which apparently answers the question of whether sodium acetate is soluable in HCL. I thought it might form a precipitate.

Presence of HCl may slightly change solubility of acetate, but for all practical purposes it will be still highly soluble salt.

 

[zoobyshoe]

Borek, I tried the "cleaning the penny" routine. I found three pennies that were equally tarnished. I kept one as a "control", put one in vinegar, and the other in salt and vinegar. The one in salt and vinegar started to brighten up almost immediately. The one in vinegar alone seemed to do nothing at first. As I kept visually comparing it to the "control" I could eventually see it was slightly brightened. The one in the salt and vinegar won hands down, however, and after 5 minutes looked nearly brand new.

The mix of salt and vinegar is distinctly more powerful in attacking copper oxide.

Thoughts?

 

[physics girl phd]

Mmmm...time to lick the mummy found in the streets of Peru, age unknown.

As an aside, salt and vinegar is often a pretty good cleaning agent for pots/pans. I always thought the abrasiveness of the salt was helpful, but I guess it must be the chemistry as well... guess this is when you get to used to using an old trick and never think about it.

 

[zoobyshoe]

As an aside, salt and vinegar is often a pretty good cleaning agent for pots/pans. I always thought the abrasiveness of the salt was helpful, but I guess it must be the chemistry as well... guess this is when you get to used to using an old trick and never think about it.

I stirred till the salt was all dissolved and simply dropped the penny in. There was no scrubbing necessary for the tarnish to clear up.

In the meantime I hunted up a good, rusty old hinge and put that in salt and vinegar. It seems to have no effect on common rust whatever.

 

[Borek]

The mix of salt and vinegar is distinctly more powerful in attacking copper oxide.

Thoughts?

It still doesn't mean you can call this mix a hydrochloric acid solution.

I know the effect, I am using it by myself, but I am not sure about the chemistry. Cu⁺ is complexed by chlorides (much more strongly than Cu²⁺). My guess is that oxides on the copper surface contain enough Cu₂O that presence of chlorides increases the dissolution kinetics and shifts the dissolution equilibrium to the right, making the process much faster.

I will try to dig something more.

 

[zoobyshoe]

It still doesn't mean you can call this mix a hydrochloric acid solution.

I know the effect, I am using it by myself, but I am not sure about the chemistry. Cu⁺ is complexed by chlorides (much more strongly than Cu²⁺). My guess is that oxides on the copper surface contain enough Cu₂O that presence of chlorides increases the dissolution kinetics and shifts the dissolution equilibrium to the right, making the process much faster.

I will try to dig something more.

I'm curious because the reaction is very definite and fast.

I scraped the edge of one of the pennies with a file and put it in the vinegar/salt. It sent up a nice little plume of bubbles from the nick. I assume it is reacting with the zinc inside the penny. (Our pennies are copper plated zinc.)

However, the reaction with steel is disappointing. A few little bubbles form here and there, is all.

@Ivan.
I was out of pool acid anyway so went to Home Depot and got some. It is, with tax, $10.75 for two gallons. (This seems to be the minimum quantity they sell; a box containing two one gallon jugs.)

It reacts pretty strongly with steel. There's a lot of bubbling and smelly fumes. Still, for all this activity it's not removing material from the screw I put in it very quickly. It may take a lot longer for it to "etch" one of your samples than I thought.

 

[Ivan Seeking]

I'm curious because the reaction is very definite and fast.

I scraped the edge of one of the pennies with a file and put it in the vinegar/salt. It sent up a nice little plume of bubbles from the nick. I assume it is reacting with the zinc inside the penny. (Our pennies are copper plated zinc.)

However, the reaction with steel is disappointing. A few little bubbles form here and there, is all.

@Ivan.
I was out of pool acid anyway so went to Home Depot and got some. It is, with tax, $10.75 for two gallons. (This seems to be the minimum quantity they sell; a box containing two one gallon jugs.)

It reacts pretty strongly with steel. There's a lot of bubbling and smelly fumes. Still, for all this activity it's not removing material from the screw I put in it very quickly. It may take a lot longer for it to "etch" one of your samples than I thought.

If the density of the stones check out I will dig around to find the suggested concentration of HCL.

My scale is supposed to be delivered on Monday.

I keep wondering if I can hook up with someone at the University and have it checked with a mass spectrometer. I don't know how big of a deal it would be to have it checked properly. That is the definitive test if you happen to have one handy.

 

[Borek]

I'm curious because the reaction is very definite and fast.

I scraped the edge of one of the pennies with a file and put it in the vinegar/salt. It sent up a nice little plume of bubbles from the nick. I assume it is reacting with the zinc inside the penny. (Our pennies are copper plated zinc.)

Gentle people of CHEMED-L helped to locate a paper in Journal of Chemical Education - Laurence D. Rosenhein, "The Household Chemistry of Cleaning Pennies", http://pubs.acs.org/doi/abs/10.1021/ed078p513 - basically it confirms my intuition that it is just a correct pH and presence of Cl^- that promotes creation of Cu(I) complexes.

 

[zoobyshoe]

Gentle people of CHEMED-L helped to locate a paper in Journal of Chemical Education - Laurence D. Rosenhein, "The Household Chemistry of Cleaning Pennies", http://pubs.acs.org/doi/abs/10.1021/ed078p513 - basically it confirms my intuition that it is just a correct pH and presence of Cl^- that promotes creation of Cu(I) complexes.

You're saying the presence of the acetic acid creates the proper pH for the Cl to bond with the Cu in the oxide?

If so, this makes a lot of sense. I realized last night that my experiment was incomplete in that I hadn't tested a penny in salt solution alone. I dissolved some salt in water and put a penny in. Nothing much happened, and I forgot about it. This morning, though, I found that the penny was very much cleaner than the "control".

Salt alone, it seems, will clean a penny, but it takes very much longer. The vinegar really speeds the reaction up.

(The salted penny, though, has a strange color now. I almost wonder if the black oxide wasn't replaced with the red oxide.)

Anyway, thanks for digging that abstract up.

 

[Ivan Seeking]

The scale arrived yesterday.

I show the large stone at 3.4 +- 0.2 grams/ml

The small stone comes in at 3.0 +-0.6 grams/ml

The volume measurements were a little crude, which is what mostly limits the accuracy for the small one. For the large one I was able to check the mass of the displaced water, which allowed for greater accuracy.

Based on this link
http://epswww.unm.edu/iom/ident/index.html

these would appear to be stony meteorites. Hematite and magnetite both have a density of about 5 grams per ml.

Here is part of the problem from a practical point of view. Some people spend years trying to find a meteorite. I found the large one in about fifteen minutes. But I did only get three hits on the detector over about 300 feet of creek bed packed with rocks. I just can't believe I could walk out and find one that fast. The odds against it would seem to be astronomical.

The guy who loaned me the metal detector has been looking for one for over three years.

 

[Proton Soup]

i wouldn't expect to have much luck at all where i live. this whole area is covered in iron ores. i remember playing with magnets as a kid, and just raking a dry sandy spot of dirt would net several tiny pieces.

 

[zoobyshoe]

The scale arrived yesterday.

I show the large stone at 3.4 +- 0.2 grams/ml

The small stone comes in at 3.0 +-0.6 grams/ml

The volume measurements were a little crude, which is what mostly limits the accuracy for the small one. For the large one I was able to check the mass of the displaced water, which allowed for greater accuracy.

Based on this link
http://epswww.unm.edu/iom/ident/index.html

these would appear to be stony meteorites. Hematite and magnetite both have a density of about 5 grams per ml.

Here is part of the problem from a practical point of view. Some people spend years trying to find a meteorite. I found the large one in about fifteen minutes. But I did only get three hits on the detector over about 300 feet of creek bed packed with rocks. I just can't believe I could walk out and find one that fast. The odds against it would seem to be astronomical.

The guy who loaned me the metal detector has been looking for one for over three years.

The density looks right, but since they didn't pass the streak test I wouldn't be confident until I was sure they had some nickel in them.

Have you gone out prospecting any more, or did you return the metal detector already?

 

[Ivan Seeking]

The density looks right, but since they didn't pass the streak test I wouldn't be confident until I was sure they had some nickel in them.

Have you gone out prospecting any more, or did you return the metal detector already?

This is the really freaky part. It only works intermittantly. That day was the only time that I've gotten it to work reliably. I suspect the wire going from the coil to the body has an issue and I was going to try to fix it, but the coil and the main unit look like they're sealed. It is designed to be waterproof. So I may try to get another one.

Note that technically they didn't fail the streak test. It wasn't dark gray or red. At most a light gray. And that was to rule out magnetite and hematite, both of which are conclusively ruled out by the density. At this point I may pay a visit to the local University. I don't want to guess about the next best move.

I'm tempted to run over to the rock shop and have it cut in half, but I'd better not... just in case that's a bad thing to do for some reason. I'm sure this is nothing special, maybe worth $100-$200 from what I've seen, but at this point I'd feel better about checking with the local expert before I do anything destructive.

 

[Ivan Seeking]

Not a good sign: I was referred to the right place but then connected to a recording saying, "if you are calling because you think you may have found a meteorite... due to the high call volume... please call this number". So it seems that meteorite hunting is now popular enough to make this difficult. I'll just have to give it a little time and see if someone calls back.

On the up side, they do still take messages about possible finds.