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Can a vlf or pi machine detect gold telluride?  Does the gold telluride have to be in large concentration in a specimen for a detector to be able to detect it?  Could a Falcon Gold probe detect a gold telluride specimen?  Thanks! for any information or tips you can provide.

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Tellurides are usually conductive so I don't think you will have a problem. I once purchased a bottle of gold telluride nuggets from Canada just because they were odd. They looked sort of like gold nuggets with zones of silvery lead like material in them. I am sure a detector would find them if they were large enough.

Just like gold or any other detectable item how well you can detect anything is dependent on how large the item is. You need solid electrically conductive masses.

See this page, third photo down http://www.see.leeds.ac.uk/research/essi/sedimentology/working-groups/gold/

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Thanks! Steve for the information.  In your opinion would the high frequency VLF gold detector, Falcon Gold probe or PI detector would give the best results in detecting gold tellurides?

It seems there are many types of gold telluride. Calaverite and Sylvanite is common to the Cripple Creek, CO and other areas of the US. Would this type of telluride be detectable?

Here's a link: https://en.wikipedia.org/wiki/Calaverite

                        https://en.wikipedia.org/wiki/Sylvanite

 

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As far as tellurides go I am not a metallurgist and so I really can't speak to the subject of which tellurides are conductive and by how much.

The metal detectors we discuss on the forum are not gold detectors. The thing they do in particular that we like is detect conductive items, and with discrimination non-ferrous conductive items. There is no real difference if the goal is detecting gold, or lead, or aluminum. The choice of detector will be the same depending on the size of the item to be detected, how deep it is, how mineralized the matrix (ground) is, and how much trash is about.

A Gold Bug 2 might be a good option, and in severe soil a SDC 2300 might be another option. The Falcon Gold Probe is a pinpointer and while quite sensitive is really only for spot checks.

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If anything should be easier to hit a telluride nugget... silver is the most conductive element we know, can't imagine that would hurt?

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Tellurium has about half the electrical conductivity of gold. Silver is the most conductive metal with gold having about 75% the conductivity of silver.

Not sure how that translates to detecting ore.

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Alloys are less conductive than pure metals and so bottom line gold telluride nuggets will be harder to detect than purer gold nuggets.

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Hi Steve and Everyone,.. 

We never hear about forum members detecting tellurides. I think I’ve seen one such questionable claim in 10 years of reading forums and pertinent literature. There isn’t much information available about detecting tellurides. I did a TreasureNet search and found several references, and examined a few reports, for example Jim Straight’s Prospecting Eluvial Placers with a Metal Detector, and Charles Garrett’s Modern Electronic Prospecting. All these references to this subject suggest without exception that tellurides are not detectable in the field. 

I’ve never detected a telluride such as sylvanite, or several others with silver present as a constituent, in Ontario’s silver country, and therefore I don’t have a sample to test. So I cannot speak directly to this subject although there must be experienced people who visit this forum who could step forward with direct, firsthand information on this subject. But meanwhile, let me tell you what I think…

Tellurides are similar to sulfides and are generally grouped with them in mineralogical texts. A gold telluride such as calaverite is not an alloy or amalgam of gold and tellurium, but rather it occurs as a result of a chemical reaction, creating a distinctly new chemical compound. Both gold and tellurium are chemically altered insofar as there is an electron exchange in their respective atomic structures. 

That means that the gold (and whatever amount of silver is present) and tellurium are not dissolved or mixed-in together, and I might add that such compounds, for example calaverite, certainly cannot be described as a metal. It is not a metal, but rather it is a telluride, not all that  different from what we describe as sulfides. In a practical prospecting context, one could anticipate that gold (and / or silver dominate) tellurides are either non-conductive or at most possibly a marginally conductive substance, perhaps similar to common iron pyrites that in practical terms is pretty much non-detectable in a prospecting field environment. 

The fact that both gold and particularly silver are excellent conductors does not necessarily influence a chemical compound’s detectability. For example, in my area we have a very prevalent silver sulfide called acanthite, depicted below, which is comprised of 87% silver. And yet it is not a field detectable substance. We do find it occasionally, but only when there is native silver present in an acanthite sample hence generating a detectable signal. 

Jim.

59b47afc963eb_0.5LBAGACANTHITESF18GB.JPG.d2e5135344cf84f38d5ca44476240fb1.JPG

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When I said alloy I meant gold/silver alloy. The "gold telluride" nuggets I purchased years ago were from Canada and identical to the photo link I posted at the start of the thread. They are simply a mixture of part gold, part bismuth telluride. They would certainly be detectable. I agree Jim most tellurides would not be. Without knowing the exact nature of the target it really is all just speculation. I spend many a day swinging a detector and finding nothing, but does not hurt to try.... unless I mess up my knee or shoulder!

Nice to see you posting again Jim. 

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Good points Jim. :smile:

Steve, Bismuth Telluride is an entirely different beast. It's the favored semiconductor for high energy applications. Unlike the element tellurium it's an excellent electrical conductor. It's probably the best thermoelectric conductor available so it's used extensively in high energy high/low heat environments. When doped with tin it's conducting properties are excellent and I imagine gold could have a similar "doping" effect.

The sample picture you linked to appears to be a gold nugget with some included tellurides rather than a true mineral composed of gold/bismuth/tellurium. The mineral that contains all those elements is the sulfide Buckhornite which is black in appearance. It is known to be associated with free native gold in the Buckhorn mine near Boulder Colorado so there is a possibility of a highly conductive detectable conglomerate occurring. It appears you have an example of that.

Perhaps that's what your sample nugget is. It would be interesting to see a picture of the included bismuth/tellurium crystals. I imagine those are rather rare nuggets.

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