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Old 09-06-2011, 03:41 AM
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Question Pyrite not detectable?

This past saturday I had a chance to try my md on a quartz stone that was supposed to have gold in it. However I believe it was mostly pyrite with some gold mixed in it.
I put my md in all metal mode turned up the sensitivity then moved the disc across the stone. Not a sound from the md. Now I know it will pick up small gold rings as iv already tested it out on a small 14k ring. But I guess it could be a filler metal that triggers the md on gold rings, I don't really know. I would have thought that pyrite would have been detected easier then gold. Am I wrong?
what's your guys experience with pyrite?

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Old 09-06-2011, 09:49 PM
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I have a lot of pyrite in my collection and none of it rings up on the detector.

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Old 09-06-2011, 09:50 PM
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Default Maybe

Maybe its fooling your machine
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Old 09-06-2011, 09:57 PM
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Iron sulfide or pyrite is a very low conductive mineral that would require a highly sensitive VLF unit to detect it.

Previous post on this forum:

http://metaldetectingforum.com/showthread.php?t=29144

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Old 09-06-2011, 09:59 PM
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Quote:
Originally Posted by fred sanford View Post
Maybe its fooling your machine

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Old 09-07-2011, 01:41 AM
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Quote:
Originally Posted by fred sanford View Post
Maybe its fooling your machine
I bet that's what it is lol.

So if it is low conducive dose that mean I'm correct about why it would pick up the ring (filler metal) and not the pyrite? As there was more in the stone then there was gold in the ring. Just curious.

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Old 09-07-2011, 11:51 AM
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Nope, pyrite will not ring up. The iron is bound up with sulfur into a non-magnetic non-conductive mineral, so no response. Just cause iron is present is no guarentee it will be detected...it needs to be conductive or magnetic like native iron. Same is true with copper....copper as a native element and mineral is highly conductive and will set your detector off but copper tied up with other materials say as copper carbonate...the minerals malachite and azurite give no response to an MD. If gold is present in the pyrite, then it must be in a high enough concentration to cause the mass to be electrically conductive or no response is given.

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Old 09-07-2011, 11:53 AM
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Quote:
Originally Posted by KingTotsalot View Post
Nope, pyrite will not ring up. The iron is bound up with sulfur into a non-magnetic non-conductive mineral, so no response. Just cause iron is present is no guarentee it will be detected...it needs to be conductive or magnetic like native iron. Same is true with copper....copper as a native element and mineral is highly conductive and will set your detector off but copper tied up with other materials say as copper carbonate...the minerals malachite and azurite give no response to an MD. If gold is present in the pyrite, then it must be in a high enough concentration to cause the mass to be electrically conductive or no response is given.
^^^^^ This man knows his STUFF!!! ^^^^

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Old 09-07-2011, 12:08 PM
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Learn something new every day.
I figured someone on here would be able to explain this. Thanks

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Old 09-07-2011, 04:08 PM
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excellent explanation...thanks..

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Old 09-08-2011, 02:29 AM
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Even if there is visible gold in the quartz, most detectors will not pick it up as it is not concentrated together. What brand and model of detector are you using?
There are only a few that could possibly detect the gold in quartz matrix. The Fisher Gold Bug 2, the White's GoldMaster Series (GMII, Vsat, GM3, GM4b and GMT) and the Falcon Probes. They all work at a much higher freq than the standard detectors.
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Old 09-08-2011, 02:43 AM
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My detector is just a radio shack discovery 1000 although iv read it's a bounty hunter in disguise. Not sure how true that is though.
I know it want pickup small gold (that's why I want a gold bug) it just threw me that it would pickup a small gold ring but not the gold/pyrite mass that was about 10 times that of the ring.

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Old 09-08-2011, 11:54 AM
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Quote:
Originally Posted by KingTotsalot View Post
Nope, pyrite will not ring up. The iron is bound up with sulfur into a non-magnetic non-conductive mineral, so no response. Just cause iron is present is no guarentee it will be detected...it needs to be conductive or magnetic like native iron. Same is true with copper....copper as a native element and mineral is highly conductive and will set your detector off but copper tied up with other materials say as copper carbonate...the minerals malachite and azurite give no response to an MD. If gold is present in the pyrite, then it must be in a high enough concentration to cause the mass to be electrically conductive or no response is given.
Yeah pretty much. There is a difference between the electrical conductance in a metal, and the conductance that we speak of in metal detecting, which has to do with how the radio signal is absorbed by the metal conducted, then produces a return radio signal.

The metals in mineral samples like pyrite rock are not concentrated enough to set off a detector. There is a huge difference in concentration between an ore and a refined metal or that metal in native form.

A gold nugget would have to be a couple of grams for an E-Trac to find it from what I hear. Maybe an AT-Pro would find one that was .5 grams, at a few inches?

The presence of these minerals collectively will however decrease the depth at which you are finding targets, most noticeably the smaller ones. That is why people are willing to pay $5000 for the GPX gold detectors, that have only some iron discrimination. They can detect the smaller nuggets at decent depth even in all the minerals that come with gold.

Most of the old sites nearby that I coinshoot are within half a mile of the iron ore vein. I am not finding many targets at all deeper than 2-3 inches., but you hold a brick of iron ore up to the detector and there is no response.

There are small brown/black sandstone hot rocks the size of BBs that stick to magnets in the black soil as well. Sometimes a hand full of dirt with them in it will set the propointer off, but spread the dirt out and it doesn't.

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