XRF Devices Recommended For Determining Metal Content Questions

Smudge_Pot

I work at a smaller regional auction business in the southwest and I am often tasked to help determine the metal content of consigned items whether jewelry, US & foreign coinage among other items. We spend a fair amount of time trying to evaluate certain items to determine the metal content and I would appreciate input pointing us in a direction of a XRF analyzer or other options that may better help us do what we do daily. Countertop and hand-held options are both helpful. We do occasionally find items consigned that are not what they are purported to be and I'd really like to find something that we would use without having to acid / ping / otherwise test items. Thanks for ideas!

MsMorrisine

We have a precious metals forum on here.

Try posting this in there, too

Smudge_Pot

Thanks MsMorrisine! Some of this applies to consigned coins...mostly fake Morgans so I thought I'd try here first.

derryb

Sigma Precious Metal Verifier is an inexpensive route ($700-$1000) for verifying PM content of coins and bullion. It does not determine content it only verifies content based on user setting of what is expected of the item. Mine has paid for itself multiple times.

Here it is identifying a fake ASE proof using one of it's three plug in probes (it also works with no probe by simply setting the coin in the center of the instrument's surface). For this test user sets to "Silver 99.9%" and then measures item. In this photo "fake" is indicated by the arrow to the right outside of the brackets. An authentic Item will show a rectangular bar inside the brackets.

Smudge_Pot

@derryb said:
Sigma Precious Metal Verifier is an inexpensive route ($700-$1000) for verifying PM content of coins and bullion. It does not determine content it only verifies content based on user setting of what is expected of the item. Mine has paid for itself multiple times.

Thanks derryb! I was unaware these were out there and cheaper than I was expecting.

jdimmick

XRF is the best although prohibitively expensive. If your doing jewelry and coins, and other stuff, its a must. But not 100% perfect either!

Sigma is good, but will not work on jewelry. I did use it once to verify a cigarette case in 18kt. Sigma can also be used to check flatware if thick enough and enough of a flat surface area to tell.

But its not perfect either. I had a guy come in thursday with a 1/4 oz gold .999 monarch round, sigma said it was good, dead center in fact, but It felt off to the touch. I been buying scrap and coins for a long time, so you just learn over the years the feel. I then checked it with 22kt acid, and it slowly faded away, shouldnt have done that being .999.

MsMorrisine

Would a sigma with a probe work on jewelry and flatware?

keets

rare earth magnets might help with Morgan counterfeits and other silver coins.

ricko

I have been debating getting a Sigma... Only because I would not have a frequent use for it. Mostly, it would just sit and gather dust. Of course, when needed, it could very well pay for itself.... Cheers, RickO

WAYNEAS

What a great little invention.
It too would only collect dust.
I would rather that dust settled onto a nice slabbed PCGS Kennedy.
Wayne

BStrauss3

Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

jmlanzaf

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

Ppp

I found the following for coins works really well for me: a rare earth magnet, weight, dimensions, sigma meter, and lastly looking for variations.
By going through these steps, in no particular order, I have found fakes. If a coin passes all then extreme high probability it is real.
🙂

pmh1nic

@jmlanzaf said:

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

The Sigma should be able to detect an issue down to about 1.5mm thickness.

jmlanzaf

@pmh1nic said:

@jmlanzaf said:

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

The Sigma should be able to detect an issue down to about 1.5mm thickness.

So, yes.

pmh1nic

@jmlanzaf said:

@pmh1nic said:

@jmlanzaf said:

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

The Sigma should be able to detect an issue down to about 1.5mm thickness.

So, yes.

That depends on how you define plating. Typically gold plating is only 5 -10 microns thick versus the 1500 microns (1.5mm) depth the Sigma can detect.

jmlanzaf

@pmh1nic said:

@jmlanzaf said:

@pmh1nic said:

@jmlanzaf said:

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

The Sigma should be able to detect an issue down to about 1.5mm thickness.

So, yes.

That depends on how you define plating. Typically gold plating is only 5 -10 microns thick versus the 1500 microns (1.5mm) depth the Sigma can detect.

Not for newer counterfeits. They are quite thick to defeat counterfeit detectors.

But the comparison is to the XRF which can also go down to maybe 1 mm, or at least a couple hundred microns.

pmh1nic

@jmlanzaf said:

@pmh1nic said:

@jmlanzaf said:

@pmh1nic said:

@jmlanzaf said:

@BStrauss3 said:
Understanding the methodologies and limitations of both devices is key to using them successfully.

The XRF reads the surface, or at high power a small way into the object. Thickly plated tungsten will fool it.

The Sigma uses induction to determine the resistance of the object. That's why you have to tell it what you are reading.

https://www.sigmametalytics.com/manuals

Select the alloy using the left and right arrow keys.
a. Gold- lists the following alloys: Pure .999+, 91.7% 22K bal Cu, 90% bal Cu, American Eagle, Krugerrand, and 98.6%.
b. Silver- lists the following alloys: 99.99% Pure, 99.9% Pure, 92.5% Sterling, 90%US pre 1900, 90%US pre 1945, 90% Coin 1960, 96% Britannia, and 80% Canadian.
c. Other - lists the following: Platinum, Palladium, Rhodium, Copper, and Calibrator.
d. Bullion- lists the following: Silver .9999, Gold .9999, Platinum, and Palladium.

Won't the sigma have the same surface problem?

The Sigma should be able to detect an issue down to about 1.5mm thickness.

So, yes.

That depends on how you define plating. Typically gold plating is only 5 -10 microns thick versus the 1500 microns (1.5mm) depth the Sigma can detect.

Not for newer counterfeits. They are quite thick to defeat counterfeit detectors.

But the comparison is to the XRF which can also go down to maybe 1 mm, or at least a couple hundred microns.

A St. Gaudens is 2.41mm thick which means the Sigma can test completely through better than half the thickness of the coin.

jmlanzaf

@pm

Not for newer counterfeits. They are quite thick to defeat counterfeit detectors.

But the comparison is to the XRF which can also go down to maybe 1 mm, or at least a couple hundred microns.

A St. Gaudens is 2.41mm thick which means the Sigma can test completely through better than half the thickness of the coin.

True. I wasn't thinking in those terms, but there are some fails out there.

https://www.youtube.com/watch?v=vl596xr8blg

MsMorrisine

Many years ago I got someone on the other side of the ocean on the phone. The person talked of 100 mils of plating on the better end stuff. (Bars)

And don’t forget for ingots, you can get drilled holes with rods inserted.

I will add this: pcgs’ coinfacts
You will get high quality pictures of genuine coins. Many cheap counterfeits (but not all) can be picked up via visual inspection.

pmh1nic

@jmlanzaf said:

@pm

Not for newer counterfeits. They are quite thick to defeat counterfeit detectors.

But the comparison is to the XRF which can also go down to maybe 1 mm, or at least a couple hundred microns.

A St. Gaudens is 2.41mm thick which means the Sigma can test completely through better than half the thickness of the coin.

True. I wasn't thinking in those terms, but there are some fails out there.

https://www.youtube.com/watch?v=vl596xr8blg

Impossible to know what the issue may have been in this situation. It could be a problem with calibration or the incorrect wand was used.

BStrauss3

All true - the skill of the operator is a key success factor.

For example, blood glucose meters are +/- 10%. Not because the technology is inherently that accurate, but because the skill of the operator varies so much.