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What have I found?
  
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navieko




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PostPosted: Aug 18, 2019 00:52    Post subject: What have I found?  

Hello,

Went out detecting with my SDC 2300 at a random dried creek looking for new gold locations. Didn't find any gold, but I found these 2 little "rocks" which sound off like they're gold or lead. You can see in the picture with the 5c coin (Australian) they're relatively small, but pack some weight for their size. The larger one on the left weighs 2.43g and the smaller one on the right weighed .84g.

I thought I'd hold a flame to the smaller one and see if it quickly melts to rule out lead, and after a few seconds a tiny bit of "crust" popped right off to expose a very metallic/silvery looking metal underneath the crust... I'm assuming the bigger one will be the same inside (they were found within a several meters of each other and apart from size look/feel identical). They're not attracted to magnet. The outer crust is quite hard and doesn't seem to scratch easily.

Under a microscope the metal looks a bit like crystalline platinum or something.

Any ideas? Should I continue heating up the smaller specimen in hopes to fully extract the metal core, and then do a specific gravity test?



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SteveB




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PostPosted: Aug 18, 2019 03:31    Post subject: Re: What have I found?  

Iron concretion is my instinct. I have a large collection of them I collected in a hole formed at the bottom of a downpipe. Many dont attract to a magnet either. I would love to understand more how they form. Possibly like a pearl or stalagtite in this case an iron rich solution builds up layers around a foreign object. So yours mau have formed around natural metal piece, or dropped ear stud, or slag from welding. Curious, I have only broken a few of mine open and they are layered dull reds/browns. I would be interested to know if there's any easy way to test what yours contains.

If you can return to the area take a strong magnet and see if you pick up more. I really think iron conretions are what you have and a magnet should find more looking the same. The location could have seen some mining/habitation in the past where corrugated iron may have been used and since rusted away forming these. If thats the case there may be secondary signs, there will be lots of concretions and some may have formed around droplets of solder or even refined precious metal.But if thats true a magnet will find heaps more though that instead formed around rust flakes. I would try to test it with a metal detector which should react to the silver coloured metal inside since the crust is a non-metallic form of iron much like in our blood so it should give an indication that further testing is worth the effort or not.
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navieko




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PostPosted: Aug 18, 2019 05:33    Post subject: Re: What have I found?  

Hey thanks a lot for the info Steve, first I've heard of Iron concretion but did a bit of reading up on it and does make sense. The seasonal creek I found them in is kind of in the middle of nowhere however it does pass under an old sealed road (via causeway) but upstream from the road it goes up into the hills and peters out, no signs of human development further upstream. I suppose there may well be enough iron junk filtering in via the causeway/road though, I found the stones downstream from the road/causeway.

So that explains the weird "crust" which had me scratching my head. Question is what is the metallic object inside... hopefully it's a natural nugget of some kind but I guess more likely to be something unnatural? And also now knowing about the process of iron concretion, I suppose it's also quite likely that the other larger stone could contain something entirely different.

I think all that's left for me to do is heat them up until the crust breaks off entirely and go from there? Like a Kinder Surprise... still kind of exciting as never know what will be found! :D
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SteveB




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PostPosted: Aug 18, 2019 06:31    Post subject: Re: What have I found?  

I wouldn’t break it just yet, just in case it’s something more important or interesting. The thing is metals are very rare in nugget form, the more often require human intervention to smelter ore or create a large intense campfire that sustains high temperature long enough for a stone in the fire containing ore to produce droplets. Plus metals quickly oxidize when exposed to air causing them to dull. So its intriguing as to what it is plus being encased makes it an interesting piece. A jeweler may be able to run a chemical test on the exposed surface and a hardness scratch should be possible too. Could be a fishing sinker or bullet projectile but not if it holds its bright silver surface. I have an odd nugget myself of a bright silver metal with no indication its cast from human activity and I'm slowly trying to find out what possibilities exist. I have hardness and rough density values only to go on myself. But its not something I want to damage in my own search and i would advise to leave it as is, maybe pop it in a small jar. Whats the hurry? If its platinum its not going to buy you a private island and it can only raise in value. Regardless the mystery is pretty cool I reckon . You can also research the geography of the area you found it to see if any old mines for metals been in that area.
Dumb question: have you poked it with anything to see if its solid or spongy? I'm wondering about old method of gold extraction using mercury to create an amalgam if this might be a blob of amalgam from someone working the spot.

Steve
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navieko




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PostPosted: Aug 18, 2019 07:22    Post subject: Re: What have I found?  

Appreciate the advice, I too was very hesitant to do anything further at least until I have further proof of what it might be... still haven't done anything further to it so I think I'll take your advice and take my time, perhaps take them to a specialist/jeweler.

The exposed portion of the metal still has it's shine/luster, seemingly unchanged since the initial exposure about 48 hours ago. Under a microscope it really looks beautiful, perhaps even crystalline in nature.

Also I haven't done a proper scratch test yet but at least giving it a little scratch with my finger nails it seems quite hard.

I am perhaps more tempted at this point to use cigarette lighter to heat up a small portion of the larger untouched piece and see if I can expose a small portion of that one as well just to confirm whether or not it contains the same material.

Would you recommend just a standard jeweler or perhaps a call/visit to my closest university and see if they have someone willing to take a look? Only I'd be hesitant giving specific location details away until I have an idea of what it is and the potential value, as I may well be able to find more with a bit of effort. ;)

I'll do some research on any current & historical mines within that area but as far as I know the only mine near that area is for limestone.
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vic rzonca




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PostPosted: Aug 18, 2019 10:53    Post subject: Re: What have I found?  

One test that might be useful, and can easily be tried at home, is a test for malleability. Malleability is the ability to bend or shape a material using compressive force. A small, sharp, hard, probe, such as an awl or stout stick pin, even the tip of a knife blade carefully pressed into the surface may leave a mark if the material is soft and malleable, which might indicate lead, conversely the test may show a brittle nature which will give you more info as what in may be. Don't stick or cut yourself. I don't think the lighter will give you enough heat or a satisfactory result. The chart is elemental metals or manmade alloys, not ores.


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SteveB




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PostPosted: Aug 18, 2019 14:48    Post subject: Re: What have I found?  

Malleability is certainly a good data point for identifying but may be difficult in this case due to small size. I would also advise against heating as toxic fumes are very possible. If it is natural metal it’s unlikely to be pure, likewise manmade really. So its probable youll release vapour containing lead, mercury or zinc or any number of toxic compounds. If you can do spectroscopy you could take a tiny sample to powder and burn in a flame and analyse the spectra.

As for where to take it, do nt bother with a big chain jewellery store. Search for assayers in your area or small jeweller that does repairs etc as they should be able to have acids theys can apply to test with. Some of them may be controlled items the jeweller is licenced to use that you are best not trying to mess with. A university might be worth contacting tooas again they will have knowledge, skills and equipment for testing there. But able to help non students depends on who you speak to. I would start with a geologist who may already know chemists and metalurgists on campus who could help, maybe a physicist who could use a mass spectrometer to analyse the metal composition. Even if its trash it could be of scientific value like that spark plug found encased in rock... an seaming impossibility. So once youve fully broken that crust its main value of its context is lost forever. Getting rich just not likely regardless and whether mines exist ir not in the area, these days you can be heavily fined for prospecting . Plus you cant find a single square mile on the surface that hasnt been documented already for mineral composition so you will find records that will tell ypu about soil and rock types in that location. Trying to be secretive is petty and counterproductive these days. If there are natural metals anywhere in the area they will have been picked over and assayed for mining possibilities and found it not worth the cost . You mentioned the road and bridge nearby plus no matter how far from everything you think you are others have been there first. Its highly likely to be trash of some sort. Let it sit untouched for a few months on a shelf then see how bright it still is. Iwould be inclined to think its a blob of solder which may remain bright and shiny indefinitely and certainly contain metals very toxic if heated. Even still a manmade object encased in rock by a natural process is damn rare and could help scientists understand the processes involved far better.
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navieko




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PostPosted: Aug 18, 2019 18:58    Post subject: Re: What have I found?  

Okay thanks, I'll make some calls and see if I can find a specialist whose geared up and willing to take a look/do some tests. Again, your advice/wisdom on this matter is much appreciated! Will be sure to update this thread when I have more info.
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SteveB




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PostPosted: Aug 19, 2019 02:10    Post subject: Re: What have I found?  

I’m keen to see how you go with confirming this, i’ve found it tricky to identify metals for lack of chemistry knowledge and skills and tools. Just looking at the photos again, you have the “cap” piece to get acid reactions on etc. a shame no-one else has likely advice yet here. If you have children in high school or know some well to ask if they can ask a science/chemistry teacher its well worth a shot. A lot of testing I know of if high school student level anyway. Plus its easier to ask and get in contact out of school. There are gemological institutes you could send it to and get a certificate identfying it but it will cost you. A local teacher pationate about rocks is easier to invite around for a beer and chat :) I like a good mystery :) BTW a geiger counter will indicate if its more radioactive than the background level (not likely), but most of all note all these things in a notebook. Anecdotal items and tests youve tried and how tests were done, with results etc. Often identifcation includes eliminating possibilities based on some of the test result, its more than just looking and seeing a shiny silver metal and I may be weird but I find it interesting finding and testing small facts about something and assembling them to produce a valid identification.
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navieko




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PostPosted: Aug 23, 2019 04:20    Post subject: Re: What have I found?  

So... an update!

After a lot of phone calls and emailing, I was only able to find one place that could do the tests to establish what the metal is, and they charge around $200 for the test (which I can't justify for something like this at the moment). Didn't hear anything back from my local university and at the end of the day, I'm too impatient for my own good...

So I decided to try and "extract" the metal from within the smaller specimen, which I figure would then allow me to do more of my own tests to at the least narrow down the possibilities, if not confirm it.

Getting the metal out turned out to be quite easy. I put the specimen into a small steel pot and onto an electric stove at full heat. I was expecting the rest of the crust to pop off bit by bit, however what ended up happening which was quite surprising, is after a few minutes the inner metal became molten and started pooling outside of the crust (see pics below, initially I took it off the stove before it could fully separate and then I re-heated and managed to fully separate the bulk of the metal).

So this process in itself ruled out most metals due to the obviously low melting temperature. From my research, this narrowed the possibilities to lead, tin & cadmium. As lead and cadmium both have a similar melting point (320+ Celsius) I found myself a small lead bullet out of the 100s I've collected while metal detecting and put it, along with the mystery metal into the steel pot and this time into the oven which was pre-heated to 250 Celsius. Since tin has a melting point of only 232 Celsius, I figured this would be sufficient enough confirmation to at the least rule out lead and possibly confirm tin.

The result? After a few minutes left in the oven, the mystery metal was molten, the lead was still rock hard.

So it seems I've found native tin inside iron stone looking rock (possibly iron oxide concretion). I say native tin, as it's my understanding that very few man-made items are made from 100% tin these days? I did try a specific gravity test as well, but my results were inconclusive (multiple tests with different results, anywhere from 7-10.5) probably due to crappy quality digital scale.

Thoughts? I've still yet to touch the larger specimen, and may go back to the location and see if I can find some more.



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SteveB




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PostPosted: Aug 23, 2019 04:38    Post subject: Re: What have I found?  

Tin? As in tin foil, as in rubbish someone threw in a fire years ago or a bushfire melted? No reason its a pure metal either, melting doesnt make it pure, smelting does which is different. Still its likely poisonous when melted and the miniscule amounts build up in your body so you will have breathed some of it, not going to die today . But being reckless and impatient well in time...

Anyway visually Id say its a blob of solder from the shapes formed. Still should have left it alone, could have been worth something one day ti a museum or collector since money seems your main interest with it. Now its destroyed as a rarity and just waste, nothing more :(
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navieko




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PostPosted: Aug 23, 2019 05:08    Post subject: Re: What have I found?  

If it was the only specimen I had I'd have been more inclined to be patient but I have another, and from my discussion with the guy at the lab, he said to properly test it would be destructive to the specimen anyway... So after what I've found I'm a bit relieved to have not spent $200 bucks just to find out it's tin.

I thought tin foil was superseded by aluminium foil after world war II... Not to say it can't have been tin foil from way back when I guess. But the one thing that still makes me question the iron concretion theory is that I've found 2 specimens, separated by at least 3-5m. Seeing as how seemingly rare it is to come by these things, how likely is it that I've found 2, both containing the same material (yet to be confirmed but likely)? And I did a pretty quick walk down that stretch of creek, I feel like I could find more specimens with a bit more effort...which again is also why I wasn't too concerned with sacrificing the one small specimen I had.

I'm still interested in taking my findings to a geologist/mineralogist as I am interested in finding out more and sharing the find from a scientific perspective... However I am human and of course was pretty keen/excited to know if I found a potential source for something much more valuable... That is at least half the reason I got into metal detecting/prospecting... The fantasy/dream of getting lucky and finding something valuable!

Anyway I'll still be back to post an update if any further developments.
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SteveB




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PostPosted: Aug 23, 2019 07:09    Post subject: Re: What have I found?  

There are non contact tools for metals testing about $15k to buy but if you find someone with one or a dealer to demo on your sample.. most other tests are destructive but that wasnt you only choice. It value was as a curio rather than financial but if you get enough out of the rocks maybe a scraper will give you a few cents.
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navieko




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PostPosted: Aug 23, 2019 08:09    Post subject: Re: What have I found?  

Obviously not worth the effort of extracting the tin for a few cents -- good thing I quickly got to the bottom of it myself then and only had to sacrifice a tiny specimen to find that out without spending more time/money/effort than I could have otherwise.

As it is though it's still a very interesting find in my opinion and I'm quite happy to still have an untouched specimen, much larger than the small one I sacrificed still on my desk... and will continue to look for a specialist within the field of geology/mineralogy to take a look and see what can be learned. I'll also see if I can find some more, and then perhaps send some samples away to be studied for the benefit of all interested in this field.

I appreciate your input on the matter, especially where no one else seemed to be interested in giving their 2 cents... but may I suggest you lighten up a little? You seem to be taking my decisions very personally. Yes I could have done more to avoid sacrificing the little specimen... but like I said, I have another untouched specimen much larger, and there's probably more to be found.

How's this? If I find more, I'll send you one -- my gift. ;)
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Don Lum




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PostPosted: Aug 23, 2019 10:41    Post subject: Re: What have I found?  

Hi Navieko,

What you found appears to me to be some once melted silver that has been poured from a crucible for the possible purpose of sand casting or other form of casting such as lost wax casting or even straw casting. The melting point of silver varies between 890 and 961 degrees Celsius depending on whether it is .925 or .999 silver.

Just a thought. Good luck.

Don

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