Testing Nuggets With Multimeter (Ohms).

[PMac77]

Hi everyone,

I've been going through the forum slowly, so my apologies for not posting much to date, I hope this question hasn't been done to death. My question is, Can you tell a Gold nugget for certain by measuring it's electrical resistance in Ohms? I've seen on line somewhere that Gold is about 2.44 Ohms @ 20 degrees C. Is this a reliable way of checking or is there better tests to conduct like a scratch test? I'm a total newbie to detecting. Thanks in advance.

Pete.

 

[Jaros]

The electrical resistivity of gold is 0.022 micro-ohm/mtrs at 20 C. Meaning you would have to have a very good digital multimeter to perform the test. The thermal conductivity is 310 W m-1 K-1at the same temperature. The corrosion resistance of gold is perhaps one it's most useful properties. Electrode potentials are a useful method for representing the tendency of a metal to corrode.
Normally just weigh it after impurities removed.

 

[user 4485]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

 

[Bjay]

As mbasko said. Theres no mistaking gold. If unsure buy a small natural nugget. Youll then know for sure.

 

[PMac77]

Thanks for the reply guys, I do have a couple of small nuggets a family member gave me, I'll study those. Thanks for the info as well Jaros I was way off. This sort of info is why I joined the forum thanks again :Y:

 

[Mackka]

Dont worry about the tiddlers mate go and get the big buggars.
Mackka

 

[Swinging & digging]

Industrial Instrument Technician / sparkie here!

A multimeter won,t tell you anything of value for resistance of a gold nugget.
Silver is the best conductor but gold is not far behind & don,t forget good old copper which is very common in electrical wiring.
Using a digital multimeter you will get a reading for your test lead resistance of 0.1 ohm just tested my Fluke meter to confirm.
On a nugget you will get the same reading as its a very good conductor.

Your readings will be the same on a nugget, silver coin & short bit of copper wire.

 

[Simon_49]

As stated in one of the above posts, measuring the resistance isn't going to be a reliable method of determining whether what you found is gold or not, most metals usually do have an electrical resistance lower than about 0.1 ohm, even Aluminium, and you also have to take into account the electrical resistance of the copper in the multimeter probe wires, a typical digital multimeter has an input impedance of 10M, or ten million ohms.

 

[PMac77]

Dont worry about the tiddlers mate go and get the big buggars.
Mackka

That sounds like the go Makka, I'll give it my best mate.

 

[PMac77]

Thanks for the info Swinging & digging & Simon_49. Certainly sounds like it's not the way to go. :Y:

 

[PMac77]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

Thanks mbasko,
What is the SG of gold? Im guessing pretty high.

 

[AngerManagement]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

Thanks mbasko,
What is the SG of gold? Im guessing pretty high.

This is a reasonable reference...

http://www.ambrsoft.com/CalcPhysics/Density/Table_2.htm

But again there are variables... Quality of water and most importantly the quality of the scales- should have 2 dec places at least and 3 is great if you can afford it.

Due to other impurities and your method and accuracy, you may not get an exact mach but if your close to the numbers. Then you are 99% there. As you will see Tungsten is close and hence why many fake gold bars have a core of Tungsten and without a good meteorological ultrasonic tester... A simple scratch test or weight or density test will not always pick up the fact that your Perth Mint bar that you got from scambay is 100% or NOT.

 

[Simon_49]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

Thanks mbasko,
What is the SG of gold? Im guessing pretty high.

The specific gravity of Gold is 19.32, that is, if you compared the weight of a cubic centimeter of Gold to the weight of a cubic centimeter of water, the Gold will weigh 19.32 times heavier than water, the old-time prospectors used this fact to their advantage when panning for Gold, since the Gold would naturally fall to the bottom of the pan.

 

[DrDuck]

Where a continuity test comes in handy is assessing whether the visible bits join up in a specie.

It may help you to decide whether to plonk it in acid or crush it.

Just be sure to research (for safety reasons) before employing even weak HF acid to dissolve quartz.

If you have an ironstone specie, much weaker acids will do the job.

 

[user 4386]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

Definitely -specific gravity

Do a search under Series on identifying minerals - part 8 SPECIFIC GRAVITY under my name for a simple method

 

[Goldseeker5000]

The only reason I use a multi meter for is to determine if the visible gold on a questionable specie is connected.

 

[PMac77]

I reckon once you find your first bit of gold you'll know without any test/s.
I've seen a heap of posts where people have asked "is this gold"? In nearly all cases if someone needs to ask if they've found natural gold then they usually haven't.
IMO there's no mistaking it. :goldnugget:
Specific gravity testing is probably the simplest method though or possibly a simple acid test kit. There's no other "gold" coloured metal that will have near the same density as gold.

Definitely -specific gravity

Do a search under Series on identifying minerals - part 8 SPECIFIC GRAVITY under my name for a simple method

Thanks goldierocks

 

[How]

Where a continuity test comes in handy is assessing whether the visible bits join up in a specie.

It may help you to decide whether to plonk it in acid or crush it.

Just be sure to research (for safety reasons) before employing even weak HF acid to dissolve quartz.

If you have an ironstone specie, much weaker acids will do the job.

Hi everyone,
Im also a newbie and was wondering how do you use a multimeter to test if gold is joined in a specie before deciding to crush or dissolve?

Thanks

 

[AngerManagement]

Hi everyone,
Im also a newbie and was wondering how do you use a multimeter to test if gold is joined in a specie before deciding to crush or dissolve?

Thanks

If you have a lump of a specie and you have a spec of gold on one side and maybe a spec on the other. Measure between the two. Should be as good a 0 Ohm (depends on you meter and leads ) if Open cct then not a joined piece of gold. Be aware iron stone may confuse you unless you know and understand the multi meter and variables.

 

[axtyr]

Here is how to test a speccie for CONTINUITY with a multimeter. In electronics and electrical we use the continuity test to check if a cable is broken or not.

Continuity means: if your speccie shows gold on two or more sides and you want to know if the gold throughout the speccie is one solid piece or just lots of individual attached pieces.

Go to Jaycar or any other electronics shop and buy yourself a CHEAP DIGITAL multimeter. Shouldn't be more than $10.00 and it should also come with batteries.

The OHMS section on the meter is in the bottom left hand quadrant of the dial.

Plug the BLACK lead into the COM hole.

Plug the RED lead into the V/Ohms/mA hole.

Turn the dial to the 200k spot and the display should should read 1. Touch the leads together and the display should read 0.

Now place one lead (it doesn't matter which one) on one of the gold spots and the other lead on another gold spot.

If the display still reads 1 then these are 2 individual pieces of gold. There is no connection between the 2 pieces of gold, i.e. the cable is broken, as per the first line of this post.

If the display changes to 0 then it means that there is gold running between the two pieces. It won't tell you how thick the gold is. As per the first line of this post, this indicates the cable is NOT broken.

This cheap multimeter can also be used for checking your cables when you have problems with them. You can find if there is a broken wire in the cable or not.

Regards Axtyr.