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My first (and thus far only) gold ring found on my EQ800 was on my first hunt.  Was a solid 14, and turned out to be an 18K gold ring around 6 grams IIRC. 

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On 11/13/2019 at 2:47 PM, Steve Herschbach said:

The one thing not all people realize is silver is a much better conductor than gold. The use of gold in electronics leads some to believe otherwise. That's for corrosion resistance, not conductivity. And then the other weird factor is adding silver to pure gold. You would assume adding a higher conductor like silver to gold would increase the conductivity of the resulting alloy. It is just the opposite. Due to the way atoms align pure metal conducts far better than alloys, so when you add silver to pure gold the conductivity drops dramatically. I've got a rare chart someplace that shows it...

conductivity_gold-alloys.thumb.png.78739818b103cc997685fca900f9a5b4.png

I modified the format of the data found here and then plotted it:  https://pdfs.semanticscholar.org/f038/b47f83d3478be37c2c69a57db722c68a36ea.pdf

Gold gets a bad rap for its conductivity, but in pure form it's the 3rd best elemental conductor after silver and copper.  (Aluminum is #4.)  Very few items we find are elementally pure but rather all are alloys.  Further adding to gold's reputation is that copper and silver alloy well so what most people call 'silver' is actually silver+copper alloy together and still an extremely high conductor.

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I was making the opposite point. Gold does not usually get a bad rap for it's low conductivity. Many people think it is the best and I was trying to explain why that is not true. Ask your average person on the street what metal conducts electricity the best and see what you get for answers. Then people are puzzled by the detector readings they get. Bad rap or not the fact I deal with every day while nugget detecting is that most natural gold nuggets are very poor conductors. Jewelry hunters have it easy by comparison.

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I believe some people also lose sight of the fact that Gold jewelry can be significantly alloyed.

i.e.

  • 18K red gold: 75% gold, 25% copper
  • 18K rose gold: 75% gold, 22.25% copper, 2.75% silver
  • 18K pink gold: 75% gold, 20% copper, 5% silver
  • 12K red gold: 50% gold and 50% copper

 

So depending on shape, weight, and alloy the numbers can vary a good bit. 

And Aluminum.... Fuhgettaboutit......alloys up the wazoo!😄

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Using the chart GB so thoughtfully provided, consider that U.S. common 14k jewelry is 58.3% gold which puts it right at the bottom of his chart, less than one-quarter the conductivity one would expect from pure gold.

Most naturally occurring gold is going to run from 60% to 90% pure though it varies wildly from location to location and sometimes even in the same deposit.

conductivity-of-ideal-gold-alloys.jpg

 

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Hi Guys,

Here is a test with the v3 on gold rings. I tried 25 rings with vdi starting at 9,10,11,13,14,15,17,18,19,23,25,27,28,32,34,35,39,41,51,52,62,75,

Pull tabs were 18,21,22,28,30,35,36,38,39,41.
These were the only pull tabs i had so there is sure to be more which is close to the gold.

Regards  Pinpointa.

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10 hours ago, Steve Herschbach said:

Most naturally occurring gold is going to run from 60% to 90% pure though it varies wildly from location to location and sometimes even in the same deposit.

My plot only shows binary alloys.  Naturally occurring gold can (and does) have more than just one other component.  Thus trying to tie down native gold conductivity even with identically shaped and sized pieces (already not valid) is further steeped in uncertainty, consistent with Steve H.'s 'experimental' findings.

Coins and jewelry composition are much better controlled.  For detectorists (the one's I think give gold the bad rap 😉), note that most US gold coinage made for circulation (specifically 1834-1933) is 90% gold, 10% copper.  That also can be seen very near the bottom of conductivity on the chart.

Speaking of gold alloy, I was watching a NatGeo TV show (Lost Cities with Albert Lin) about the 16th Century Conquistadors trying to find a huge cache of gold in what is now Columbia, South America, what they called 'El Dorado'.  The natives in the area had lots of gold items which were in fact gilded, although the Spaniards, in their greed, assumed they were pure gold.  The local museum curator was talking about how those natives alloyed the gold with silver and copper.  I was wondering if rather they just used the natural occuring alloy.

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I believe what maybe happening here is...... yes what gold is mixed with in jewelry..... but also size, density, and shape.   Playing more with density than before.  But i dont see anything changing when it comes to what you want to dig on a beach....... its still just above a penny and under even for high K gold.

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