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Help Identifying Potential Platinum Nugget


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11 minutes ago, F350Platinum said:

Whatta ya bet this person doesn't come back? Hope so, but... 😀

You touchy-feely types...  (Sigh) :laugh:

Steve could probably give you some statistics on the number of people who make a single post in this particular subforum and then never come back.  What does he call them, 'drive by posters'?  Some are truly curious in general but I suspect 99% think they have something valuable (usually a meteorite worth thousands or more) only to be told it's lump of coal.  Deflated, they return to their real world.

Native platinum is very rare but does exist and I think is found in the Pacific Northwest.  I hope Dringle1122 has a Pt nugget.  Maybe he'll be an exception to the rule and stick around even if he finds out it's worthless slag.

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3 hours ago, GB_Amateur said:

0.01 g and even 0.001 g precision are often needed for determining densities of small items just to get within 10% accuracy.

The little calculator quoted above computes the uncertainty propagation and does the balance of their contributions, which can show you what may work (try 0.1 g for the scale uncertainty and look at pretty wide range of likely densities that it produces for example due to mostly imprecision in estimating volume).  But it will not account for gross errors like bubbles etc.

https://docs.google.com/spreadsheets/d/1Srt7cy0Fx_xkNjQO7IVXo-aK01jEYygS_W0VQZAbTCQ/edit?rm=minimal#gid=0

 

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Hey all, OP here. 😀 appreciate all the responses. I'm gonna have to look into that density deduction method more when I can get a good scale to work with. I know it wasn't the safest move for preservation but I dunked the nugget in meuratic acid to deduce aluminum/alum containing amalgamations and there was no reaction. I also hit it with a large propane torch for like 3 minutes and it held up it's shape.

 

Also, to be more specific. I live on San Juan Island in the far northwest corner of Washington. After a couple Google searches I found that 8 mines in the state potentially produce platinum. Sooo, I think unless I can get a good scale, my best bet would be to find a jeweler. Trouble is, I'm on a small island so hopefully I'll be going mainland sometime soon. Will keep y'all updated and thanks again for the tips. 

IMG_20230109_211256.jpg

IMG_20230109_210747.jpg

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Also, love the "drive by" posting comment. I am more of a round trip/drive thru Rockhound and numismatic for the most part. If it's slag, it's slag. I am here for the journey, the learning, and the community 😌 

I'm a drive thru mycologist tho, not gonna lie. Once I find out my LBMs that I misidentified give me bad BMs I take the mycologist hat off for my own health

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On 1/8/2023 at 9:46 AM, jasong said:

I would say not platinum - based on what appears to be a whitish oxidation occuring. I don't think platinum oxidizes white, think it's more brown to black. Lead will oxidize white though (think of the coating on an old dug up bullet), as will a number of other more common metals that are harder than lead. 

The good old density trick described above will tell the difference between lead and platinum. The key is doing it accurately though, as a lot of people who try are not very careful and it only takes a little inaccuracy to skew the result.

Also forgot to mention after I nailed it with the propane, I noticed a couple areas with some marroon that may or may not have been there before. Not a lot, just a couple areas. I don't even know if oxidizing occurs from heat in this case but yea

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Glad you're back Dringle, and sorry for the remarks but we do get a lot of "drive by" posts in this forum. 😀 Also glad you have a sense of humor 🙄

You should follow your posts with notifications so you know when someone has responded.

Taking the specimen to a jeweler would have been my next suggestion too, if you haven't done that you will be surprised at what they will do for you for free. Anytime I find a ring without hallmarks I suspect is a good one my local shop will help me, and they encourage me to do so.

Looking forward to future finds and potential numismatic discussion!

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9 hours ago, Dringle1122 said:

I'm gonna have to look into that density deduction method more when I can get a good scale to work with.

Determining the volume is the tricky part since your specimen is pretty small and you're effectively weighing an equivalent volume of water.  Let's estimate.  Say your specimen has a volume of 0.2 cm^3.  That amount of water weighs 0.2 grams.  A scale with smallest possible reading of 0.1 g would not tell you nearly enough.  A scale with a smallest possible reading of 0.01 g would give you an absolute uncertainty of 0.01 / 0.2 = 5%.  If you made no systematic errors (e.g. no bubbles, use tiny thread) then that should give a pretty good indication of its density.  A platinum nugget (likely an alloy, not pure platinum) should have a density in the neighborhood of 20 g/cm^3 (specific gravity of ~20).  If you got close to this (anything over 15 g/cm^3 would be significant), you would not only easily eliminate aluminum but also those intermediate metals and their alloys which are quite common.  (That crusty white caliche -- might be the wrong word so I'll let the geologists correct me -- is likely to be a bigger factor in reducing the density than any alloy.)

There is a modification of mcjtom's specific gravity determination description which might help, but it's a bit more tedious.  It involves suspending the specimen from the scale (i.e. below the scale) and submersing it.  The advantage is that the total weight of the water and its container is irrelevant.  You could use a teacup or a swimming pool!  If the scale's dynamic range is overly limited, his method will cause the scale to max out, preventing the volume determination.  But I would try the simpler method first and resort to mine only if that overload occurs.

In order to do the suspension method you'll need to make a yolk that sits on the scale but extends below the scale.  Think of an upside down trapeze....

For small items like yours I use monofilament sewing thread.  (I bought it at JoAnn's Fabric.)  It's tricky to work worth (almost invisible) but with it you can ignore the volume displacement it causes when immersed with the sample.

Here's an affordable(?) scale I own which will probably help you get within 10% of the specimen's density.

https://www.amazon.com/gp/product/B0012LOQUQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

P.S. Glad you're sticking around.  😁

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18 hours ago, Dringle1122 said:

Also forgot to mention after I nailed it with the propane, I noticed a couple areas with some marroon that may or may not have been there before. Not a lot, just a couple areas. I don't even know if oxidizing occurs from heat in this case but yea

Makes me think of what old nickel coloration looks like when dug out of the ground. I think some of it comes from copper in the nickels or something though.

No idea though...I'd have done a density test already, quickest way to tell what it isn't. 😁 Just put a container of water on the scale, zero out, then dip the sample in on a string. The weight of the water displaced is equal to the volume of the sample - since water density is simply 1g/cc. So the additional weight on the scale in grams will be your volume in cc. Divide the dry weight by the volume in cc and you'll get a density in grams/cc, which is standard. Takes about 20 seconds to do.

Trying to calculate volume by displacement (Archimedes method) is way too prone to error - estimations, meniscus, etc. Don't use that method.

Send it to me with return postage and I'll XRF it for you if you can't find anyone to ID it.

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1 hour ago, jasong said:

Send it to me with return postage and I'll XRF it for you if you can't find anyone to ID it.

On many forums that would be taken as a joke, so I will add that Jason really does have an XRF gun, and is a man of his word.

You may very well have a platinum nugget. I only found one of 50 years of prospecting, and it's only half the size of a grain of rice, if that. I do hope yours is the real deal - that would be awesome. :smile:

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