I may have found a couple of meteorites

[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.

 

[Loren Booda]

Please forgive the diversion, but how much are meteorites worth?

 

[Ivan Seeking]

Please forgive the diversion, but how much are meteorites worth?

They have a wide range in price depending on rarity, type, size, appearance, and pedigree. Pieces of historic strikes can be exceedingly valuable. The prices seems to range from from perhaps $100 for a small, common meteorite, up to "priceless".

Here are some stone meteorites for sale. They range in price from about $200 to $3400. For comparison, my large stone is 34.9 grams.
http://www.aerolite.org/stone-meteorites.htm

 

[zoobyshoe]

The third possibility that remains in my mind is that they might be some form of old foundry waste. That's why I brought up cast iron before and why I asked if you'd gone out hunting again. The more you find that you're sure aren't natural ores, the more likely it would be you're downstream from some old foundry. The further back in time you go the more irregular in composition the "slag" from such a foundry might be, with each frontier cottage foundry having more and more of it's own idiosyncratic "recipes" and procedures. With the flooding carrying things far from their source, they might be slag from a foundry 50 miles upstream that went out of business in 1824.

 

[Ivan Seeking]

The third possibility that remains in my mind is that they might be some form of old foundry waste. That's why I brought up cast iron before and why I asked if you'd gone out hunting again. The more you find that you're sure aren't natural ores, the more likely it would be you're downstream from some old foundry. The further back in time you go the more irregular in composition the "slag" from such a foundry might be, with each frontier cottage foundry having more and more of it's own idiosyncratic "recipes" and procedures. With the flooding carrying things far from their source, they might be slag from a foundry 50 miles upstream that went out of business in 1824.

Something manmade seems the most likely alternate explanation. However, I know where the headwater is for this creek - it's only a few miles up in the hills - and there is nothing like a foundry between here and there, and never has been. I could see the possibility of an old abandoned mine being in the area but don't know of any. The other problem is that I would expect a higher density for any kind of alloy.

Another clue suggesting they are meteorites is that they are ferromagnetic, but not strongly so. If it was a chunk of metal, I would barely be able to peel it from the magnet.

 

[zoobyshoe]

Something manmade seems the most likely alternate explanation. However, I know where the headwater is for this creek - it's only a few miles up in the hills - and there is nothing like a foundry between here and there, and never has been. I could see the possibility of an old abandoned mine being in the area but don't know of any. The other problem is that I would expect a higher density for any kind of alloy.

Another clue suggesting they are meteorites is that they are ferromagnetic, but not strongly so. If it was a chunk of metal, I would barely be able to peel it from the magnet.

You're right about the magnet if it were pure cast iron, but by "foundry waste" I meant some kind of slag: what they skim off the top of molten metal before they pour it. This would not have a high iron content.

I'm not sure you can be 100% certain there was no one casting iron in the area, ever. A local farrier or blacksmith might have had a side line casting plows or skillets, or bootjacks, or ornamental door knockers for that matter.

The reason I'm going on about this is that, while you say they didn't fail the streak test, they also didn't pass it. A meteorite should leave no streak. And, as you pointed out, you found two within a short distance of each other, which is unlikely for meteorites.

 

[PAllen]

Don't know if this has come up, or is practical, but if you cut off a slice with a diamond saw, and grind on a lap with fine grit, nickel-iron meteorites look pretty distinctive. Of course, I (long ago) had all this equipment for gem cutting. Presumably, you may not have ready access.

 

[Ivan Seeking]

You're right about the magnet if it were pure cast iron, but by "foundry waste" I meant some kind of slag: what they skim off the top of molten metal before they pour it. This would not have a high iron content.

I'm not sure you can be 100% certain there was no one casting iron in the area, ever. A local farrier or blacksmith might have had a side line casting plows or skillets, or bootjacks, or ornamental door knockers for that matter.

The reason I'm going on about this is that, while you say they didn't fail the streak test, they also didn't pass it. A meteorite should leave no streak. And, as you pointed out, you found two within a short distance of each other, which is unlikely for meteorites.

Good point. There was never a large foundry, but there could have been a small operation on a farm. We are just about at the end of civilization but there are a few more farms beyond here.

Also, the odds are a problem. If this is a meteorite, I must hold the world's record for the shortest hunt that ever produced one. Seriously, fifteen minutes from start to first find, is just crazy.

 

[Ivan Seeking]

Don't know if this has come up, or is practical, but if you cut off a slice with a diamond saw, and grind on a lap with fine grit, nickel-iron meteorites look pretty distinctive. Of course, I (long ago) had all this equipment for gem cutting. Presumably, you may not have ready access.

I was hoping to run this by an expert before doing anything destructive. If I don't hear back from the meteorite lab soon, I will probably have it cut. We do have a gem shop nearby.

 

[Ivan Seeking]

while you say they didn't fail the streak test, they also didn't pass it. A meteorite should leave no streak.

I meant to respond to this. Well, yes and no.

A meteorite, unless it is very heavily weathered, will not leave a streak on the tile.

http://epswww.unm.edu/iom/ident/index.html

Is this heavily weathered? I interpreted the result to be indicative of something other than magnetite or hematite, but not definitive or strongly suggestive of a particular answer, beyond that.

 

[zoobyshoe]

I meant to respond to this. Well, yes and no.


http://epswww.unm.edu/iom/ident/index.html

Is this heavily weathered? I interpreted the result to be indicative of something other than magnetite or hematite, but not definitive or strongly suggestive of a particular answer, beyond that.

That's the thing, yes. They don't explain much about the "heavily weathered" possibility, what kind of streak that would leave, what other features it might have, how common it is.

There has been a resurgence of old tech among hobbyists such that people are melting and casting iron in their backyards today:

http://www.youtube.com/results?search_query=melting+iron+at+home&aq=1&oq=melting+iron

This indicates that it was something any Smith might have been able to do on his own, no huge foundry operation needed. (You can actually even melt iron with charcoal; no coal or coke necessary.)

I know that Captain Cook's ships had an obligatory blacksmith on board to repair any broken iron fittings. While I've never read this, I would assume any cavalry or wagon train on the move would also have one, given all the horse shoes and wagons that needed tending to. Any logging operation might also have a mobile blacksmith as would any railroad crew, I think, pushing into a wilderness. There are plausible reasons you might find man made iron slag just about anywhere. So, if they're not ores, and not meteorites, that's what they might be.