Electrum Gold?

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Hey Rob
I thought I would start a new thred on this nugget, it is an odd one.
Well you've held and seen it up close so I'll describe it for everyone else here.
I suspect it could be a Electrum nugget.
Its an Az. find, its weight is 149 grams or 4.7 ounces.
When I first found it I thought it may be a meteorite or silver nugget but after I cleaned it I could see what appeared to be gold in all the low areas and crevices. Its very heavy for its size and has more of a white gold look to it on the high areas. I suspected it has a higher silver content but when
I tried a sulfur vapor test on it which usuly turns silver black in matter of minutes, but all it did was highlight the gold.
It is a mystery nugget for sure that's why I would like to
get Eric to scan it with his hand held XRF analyzer. I could ship it to him if he is not going to be out this way anytime soon.
Here are a couple photo's I took of it in different light.as I lower the light the gold becomes more obvious.
The gold is easy to see with a 10X.
It has a leafy texture to it and some nice quartz crystals down in the pockets when you look at it up close.
Oh also forgot to add, There's no rust and it's not attracted to a super magnet.


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Hey Bob,

A friend of mine that is a geologist owns one. He paid over $12,000 a few years ago for it. I believe it was on Olympus, but not sure what model. I broke down stuff into the PPM. He's always traveling, but if he makes it back into the valley anytime soon, I can see if we all can get together. I have some ore samples I'm holding for him to test and a few unknown nuggets I have found.

That's a great specimen and would be interested in seeing what the metal composition is. I personally have seen the piece in person several times.

P.S. When we going to take a trip into there and see what else is around? :ph34r:

Talk with you later,

Rob Allison

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Yo Bob... That is a beautiful specimen for sure!!! Is it at all possible it's silver color is merc? I've seen some nuggets that looked like that that got either heat or nitric treated and came out gold ... But hard to tell from photo ... Awesome gold any way you look at it ... Cheers, Unc

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Sounds good . I can wait no problem. I know you got a lot on your plate right now especially with you daughter being sick.

I want to get back there too.

Uncle Ron

Im reasonably sure its not a mercury coating but Im glad you brought that up.

Its hard to get good pictures. Btw how you doing up north.

Frank C

I was staking some claims down south for a friend of mine at the end of the day I thought I'd get out my 2100 with a mono and I hit it in about 20 minutes. I did not think much about it at the time we were busy and had to move to another area. as a matter of fact I really didn't take it seriously until I cleaned it and saw the gold. It was an easy hit only about 5-6" deep. It was under a quartz vein in rolling hills and I don't have much doubt that there could be more. AzNuggetBob

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Hey Bob... Oro Blanco area? That would definitely make sense ... We got our first day of beeping in Monday with tons of trash from some very old workings ...Square nails and an old fishing lure on top of an old tailing pile were our only finds besides dozens of bullets and trash ... but the weather is awesome ... low 80's and gentle breeze ... patches have plenty shade ... Hitting an old hydaulic pit next ... Cheers, Unc

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Uncle Ron

I'll take that 80 degree weather. it doesn't even get that cold here at night!

your comment got me thinkin about the mercury so I did a test just to make sure and it is not coated with mercury.

I can only do some tests without damaging the nugget. I can do a jewelry scratch test on it.

I need to get a fresh kit mine is old and unreliable. (old acid)

Also Im a little concerned that test wont prove the actual karat because of surface leaching.

to do that I would have to grind a deep window in the nugget and I dont want

do that. But a simple scratch test will confirm the presence of gold and silver.

Oro Blanco? good guess but I cant confirm or deny it. :)

Find some big ones, AzNuggetBob

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Thanks Jim

I agree Eric Melchiorre is the guy for this nugget. it fits into his field of study well.

He does have all the right equipment to properly examine this nugget without damaging it.

The quartz vein I found it near was thin and not well structured and may just be surface pocket.

but another thing that strikes me as a little strange about it,

is it seems rather large for secondary lower temp. precip. specimen in general.

The nugget only shows signs of mechanical weathering on the high areas of its surface so I suspect its locally derived but also shows signs of chemical weathering probably from the natural oxidation of the silver and may be why it only shows gold in some areas of the nugget.


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Well... my guess the nugget is likely epithermal... Epithermal deposits have been

reported in the following Arizona counties T.B. Nolan 1933):

Mojave, Yuma, Santa Cruz, Pinal, Cochise, and Graham.... Epitherma precious

metal deposits are small and easily overlooked. Oatman and Kofa are two

examples.of a larger deposit. The silver-gold ratio varies and is known as electum

if more than 20% silver.. Some epithemal deposits have been known to be worth

drilling as they have been found to be Carlin-type at depth.

A classic example of a large epithermal silver-gold deposit is the Randsburg and

Stringer Districts just 120 miles NE of Los Angeles. More than $25,000.000 were

recovered, mostly during the early days 1895-1942.

In 1984 Glamis Gold LTD acquierd the rights to the Yellow Aster and Baltic and

drilling indicated a large amount of Carlin-type gold and silver. From 1987 until

2003 they were actively open pit heap leaching, Over 1,000,000 troy ounces of

gold were recovered, but due to economic conditiions that existed in 2003 Glamis

"shut'er down amd moved to the Glamis Marigold Mine Operation in Nevada.

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Thanks I really appreciate your opinion on it. funny you mentioned the Kofa and epithermal deposits. I had forgotten about this,

I worked near there in the 80's on a smaller heap leach operation and we re-milled the over size and were getting almost three ounces to the ton on the original mine tails and it ran about 60-40% gold/silver.because of that the 10 ounce bars we poured had a light gold color.

I found some old photo's of the first bar I poured there. I remember I was wearing a fleece lined levi jacket to do the pour to protect me from the furnace blast.(dumb) :spank: That's all we had. In the second photo the bar was still hot in my hands,we were excited!. :)

I was told that originaly the high grade from that mine ran as high as 14 ounces to the ton. Well hopefully the outcrop

I found is just the tip of the iceberg so to speak. won't know for sure until we get back on it.

Thanks again Jim, AzNuggetBob



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Howdy All... I thought I would add more to this post regarding electrum gold. I understand that

electrum is a mixture of silver and gold... It has been said that if the silver content is more

than 20% the silver/gold mixture is known as electrum.

I will now add.... electrum is commonly found in epithermal precious metal ore deposits.

Epithermal deposits are low temperature deposits associated with volcanic extrusive "lavas."

Many epithermal deposits, since they are associated with the volcanic extrusive lavas,

are often shallow and of minor importance, maybe only a "hit and miss" bonanza that

yelded a only a few ounces of ore or placer before bottoming out .

The lavas are mostly fissure veins associated with the mounain building--- massive faulting

and uplift--- that occured during Tertiary time. Thus, epithermal deposits are associated

with the "ring of fire" band of earthquakes and volcanism associated with "plate tectonics."

The Great Basin Provence of Nevada, including the Mohave and Porphry Copper Blocks

andthe Rio Grande Rift is a large metallogenetic area which hooks around the Columbia

Plateau which is capped with non-metallogenetic basaltic flows.

This is explaned in the GOLD and SILVER DEPOSITS of the BASIN and RANGE

PROVINCE WESTERN U.S.A. edited by Joe Wilkens jr. Arizona Geological Society

Digest Volume XV 1984. Arizona Geological Society Publications. PO Box 40952.

Tucson Arizona 85719. (It is not an easy read and thus likely used copies can be found

by a Google search.)

For the more serious prospector/miners... Comments good and bad welcome...Don't be

bashful ... Let therm roll!... js

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AzNuggetBob has posted some excellent information on electrum gold. I believe this

thread should not be lost in the "sands of time" The last two posts have been mine so

as to "Bump" this thread in the hope to encourage more replies on epithermal precious

metal ore deposits.

Both Reno Chris Ralph and I have information on epithermal deposits: Reno Chris in

"Fist Fulls of Gold" ~~~ Part lll, C., "Nevada's Epithermal Gold & Silver Deposits."

Read from pg. 192 through the Pacific Ring of Fire and elsewhere througout the text.

One of Chris Ralphs' articles in the ICMJ "Basic Geology for the Independent Miner---

Part V., mentions "epithermal types of deposits (ICMJ May 2006).

As for me, as a native born forth-generation Nevadan, I have been aware of epithermal

precious metal ore deposits since I was a kid. My grandmother was at Clifford,

Tonopah, Manhattan and even Ellendale back in the early days (1906-1912). One of my

books, ADVANCED Prospecting was written with emphasis on epithermal deposits

and how to metal detect them...

Both "Fists Full of Gold" and "Advanced Prospecting" are available through Rob's store.

As time goes by and with the continued development of "gold-specific metal detectors

shallow epithrmal precious metal ore deposits, both overlooked silver/electum/gold

placers will be found.

Also, by googling/bling or other search engines, there is considerable information

on the internet.... start by "epithermal ore deposits in the great basin provence,"

and other wording variations. Best, jim straight

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No new updates on the nugget, I have not had the nugget tested yet. I had for most part forgotten about these types of deposits until I found this nugget. I have been doing a lot of research on it lately and was surprised to find how many "known" low temp epithermal deposits there are out there. AzNuggetBob

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Bob... it would be a thought if your nugget could be tested for its silver-gold content.

A scanning electron microscope or another non-distructive "camera" could identify

it. I haver a copy of "Mineralogy of Arizona, third edition.To my surprise on pg. 211

electum is barely mentioned:

#Electrum (gold-silver alloy: ("argentian gold") Cochise County: Bisbee, Warren

district, in ores of the Campbell mine.

Gosh, it could be precious metal epithermal type ore deposits associated with

the volcanics is not well known by Arizona prospectors. They have alway known

to be easily overlooked "hit and miss" deposits..... jim straight

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Howdy Everyone who is reading this post. I am 'bumping' this thead regarding "electrum"

by 'replying to electrum gold' again. As you know electrum is an alloy of silver and gold.

AzNuggetBob has posted some pretty good stuff about electrum gold which is often found

within an epithermal precious metal gold deposit. Bob has also posted some nice photos

of whay may be a nice electrum gold nugget. Also, Bob posted seveal photo snapshots

regarding his experience while pouring electrum nuggets at Kofa...

Today, modern gold specific metal detectors are very capable of seeking out and finding

here-to-for unknown Epithermal precious metal deposits that have formed shallow,

scattered eluvial "hit and miss" paystreaks and pockets. Some of these deposits may

be within the the top few inches and can even be sighted during a rain-storm as a "sunbaker"

because of their sheen when wet. Therefore, being first is important... jim straight

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Well Jim

I'm thinking about going ahead and doing the acid scratch test (jewelry test) on the nugget. I got a new kit with silver and platinum also included.

I'm thinking its not going to do much more than leave a small shiny spot on the edge anyway. at least I can get a idea of the gold/silver ratio. thanks for your input here. I may put more up on these types of deposits also,

I've been doing a lot of research on them lately and have added a few more places to my fall hit list. It's just a bit to hot for me to pursue them right now. most of them are 2000 feet or less elevation and hot. AzNuggetBob



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Hey AzNuggetBob,

I have several dozen smaller Electrum nuggets ranging from about a gram to 1/4 ounce in size. They are all from a placer South of Phoenix. This is the only location I ever found Electrum in Arizona, but I know there are a handful of locations that probably produce them.

I will try to dig up a few pictured of them.

Rob Allison

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Thanks for the suggestion. I'm going to look into that and see if i can get some better more accurate results.

Hey Rob

I would like to see some photo's of those nuggets. I'm curious if they have similar character. have you ever had them tested for karat?

Well guys I decided to do the acid scratch test. whats funny is it answered some questions and created a mystery.

take a look at the results and I'll explain below. I had to brighten the photo at photobucket so you could see the metal scratches through the acid.

I tested it against my 14k white gold wedding ring.

shhhhh don't tell the wife. :ph34r:


It passed the 10k and failed the 14k.

Did you notice something else in the test photo, it seems to pass the platinum test? I really have my doubts about the platinum.

I guess we need more tests. but from what I see here it seems to be around 12K or 50% gold/silver- Platinum?

Take care all AzNuggetBob

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