What does lead or silver look like
Posted 23 May 2007 - 01:08 PM
Posted 23 May 2007 - 01:40 PM
Posted 23 May 2007 - 04:50 PM
Posted 24 May 2007 - 12:16 AM
It should though, it's metal.
Silver is funny, there are a lot of other metals that look like Silver.
Posted 24 May 2007 - 10:45 AM
Posted 24 May 2007 - 12:22 PM
Heres a pic of hematite (left) and molybdenite (right)
These are in natural crystal form. I guess I should ask if the mystery item is malable or flexible ? If it shatters then that would narrow down the search.
Both of the minerals above can become placer nuggets
Are you detecting them , or are these items showing up in pan concentrates?
Posted 28 May 2007 - 10:26 AM
I’m thinking when you use the confusing term “raw”, you are really asking what does lead, silver or maybe even platinum look like in nature, as in naturally occurring as a mineral or metallic ore. Often, without a lot of experience, you can’t visually determine the metal content of any mineral sample by it’s color alone. Some form of field or lab testing is needed to determine which metal or a combination of metals you have.
For example; lead almost never (<1/10 of 1%), occurs in a metallic form in nature. The different lead ores (galena, anglesite and cerussite) have to be processed with heat to get metallic lead. Silver does occur naturally in a metallic form, but more often as an amalgam or an alloy with non-metals such as chlorides and sulfides. And platinum is found in a metallic nugget form, combined with iron, nickel, cobalt and other PGMs.
Arizona is not known for naturally occurring lead, so if you do have lead nuggets, it’s probably man made. Maybe some old musket balls. It might be silver nuggets, but it would require testing to be sure. And, just to add a little more confusion to the mix, the elements of arsenic, antimony, bismuth, plus a list of other minerals are silver in color. I once witnessed a young geologist mistake antimony for silver, based on the color only. Talk about some misled silver mining investors. It happens…duh.
I would suggest that you continue collecting all the heavy nuggets you can find, and testing the less than perfect ones. You can do some quick checks in the field like a streak, hardness, cleavage and crystal tests. And if everything still looks good, send a sample to a lab for analysis. Then you’ll have a better idea if you are dealing with pennies/pound or dollars/oz nuggets.
Let us know how it works out for you. Good luck.
Posted 29 May 2007 - 07:36 AM
Thanks John for your reply. It sounds as though you have a good deal of knowledge in this field. I have known many nuggetshooters who "say" they have found galena and it's possible they were mistaken just as I may have been with the piece I found. I was going by the weight, color, and softness when I assumed it was lead. Would a specific gravity test tell for sure what it was? Thanks.
Posted 29 May 2007 - 11:44 AM
Rock Hound that is the material I was mistaking for platinum I think. and yes they are coming from metal detecting. But still no gold
Hey Russ I think I also have a few pretty good size nuggets of what your gelena but let me ask you another Question I took a file to one of the nuggets and it revealed a metal soft and shinny like lead what is it ? because recently I found another peice of what I assumed was the same mineral it was in quartz matrix kind of a toothy looking stuff but I smashed it and it shattered so 2 identical looking minerals and 2 diffrent results.
aussco 999 I'll give you the tough ones. What are PGM's. I know they say that gold is where you find it but I'm working down here in southern Arizona would it be poosible for me to find a Platinum nugget in this area. What exactly is white gold and does it also accure in nugget form. so being in the Tucson are I have a metal detector and I use it but I at least find some thing by digging and panning. could you tell me what the grayish material is at the very bottom of the pan its very fine and pretty heavy or it would not be there with the gold black sand and garnets at the end of the process or could it be white gold or platinum ?
Thanks You guys are a great resouce and I really apprecite your help. I am still following up on the advice I got awhile back about cleaning up the bedrock out on one of the claims and after I fill the buckets then I use the detector setting off in one diretion or another. I have become a pretty good panner and I am learning to use the Geo-communicator (what a resorce that is) wish it zoomed in a little closer. when or if I find my first nugget I will either take a picture myself and post it or I'll get direction from you all
Posted 30 May 2007 - 08:11 AM
PGM's refer to the Platinmum Group Metals being the precious metals.
The problems with doing a specific gravity test as I see it is that there is only a slight difference in the SG between silver and lead. It's fairly easy to do the aqua rigia thing with silver, but of course you would lose the nugget. Of course there's a big difference in melting points, but again, you'd lose the nugget. Maybe someone else has another idea. Here's a chart of SG and melting points. I'm looking for one on hardness if anyone has one...... rf
Metal Symbol Specific Gravity Melting point (F)
Iron Fe 7.87 2802
Nickel Ni 8.90 2651
Copper Cu 8.96 1981
Silver Ag 10.49 1761
Lead Pb 11.34 621
Palladium Pd 12.00 2831
Gold Au 19.32 1945
Platinum Pt 21.45 3224
Quartz - 2.65 -
Limestone - 2.65 -
Posted 30 May 2007 - 11:45 AM
As usual, I might have said something that sounded a bit confusing, so let me clarify a couple of things. Yep, I’ve a fair amount of knowledge with galena as I was the project manager on a galena mining/milling operation for a couple of years before it was sold to another company. I’ve never tried it, but I do think a metal detector will sound off on galena as it’s mineral composition is about 87% lead and 13% sulfur. But, the mineral galena would never be confused for a metallic lead nugget like what Fishing was referring too.
Galena has a very distinctive crystal structure that makes if one of the few easily identifiable minerals. The only thing that really changes in the crystal appearances is the amount of contamination in the galena. On our project, the galena had a high amount (40 to 60 oz/ton) of argentite (silver sulfide) in it.
FYI, an easy field test for argentite in galena is, break the sample open and expose a new surface, rub your thumb one time across the surface, if you see a very black streak on your thumb, your sample contains argentite. If it’s a BIG black streak, send the sample off to a lab for testing, you may have just found the next BIG silver mine, with lead as a by-product. If so, let me know and I will tell you which refinery will pay you the highest prices.
IMHO, I think all rock-hounds/metal detectors should always carry a pocket mineral field guide book with them, and become familiar with some of the basic mineral field tests. For example, galena is brittle (because of the sulfur) when cut or crushed, and would not be described as soft (malleable) like refined metallic lead. Arsenic and antimony are also brittle, but if your sample is soft (knife cut), it might have been native silver???
Simple answer is; pick up everything heavy, and test, test, test.
PGMs in nature are Platinum Group Minerals. They consist of the 6 elements on the periodic table to include (the heavies), platinum, iridium and osmium, and (the lights), palladium, ruthenium and rhodium, combined with each other or some other contamination like iron, nickel or cobalt. Refined PGMs are Platinum Group Metals. AZ has no known economical PGMs deposits.
White gold in nature is most likely either electrum or amalgam. Electrum is a gold/silver alloy in which the percentage of silver is higher than 25%. An amalgam would be gold covered with mercury, which under the right conditions, be naturally occurring. Very often in old mining areas, it’s a man made process.
Any heavy gray material showing up in the bottom of your pan could be several things, bird shot, amalgam, barite, calaverite, cassiterite, cerussite, cobaltite, columbite, corundum, galena, hematite, platinum, pitchblende, scheelite, siderite, silver, smithsonite, sylvanite, thorite, wolframite or zircon. And, every thing on this list is found, to some degree, in AZ. Also, this list reconfirms the need for better field identification of minerals and follow up lab testing. You may have just discovered the next Big One… so keep on looking, and always ask questions.
Posted 30 May 2007 - 04:17 PM
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