We have previously written about the need to use XRF technology to confirm or identify gold and other precious metal content in jewelry, decorative pieces, coins, and other items. This time of year can bring the best out of people, but occasionally it brings out the worst, and we have warned jewelers, pawnbrokers, and gold buyers that they need to be aware of scams during the holiday season. We’ve noted scams involving fake gold bead necklaces, coins that don’t make the grade, bad Krugerrands, and gold-plated tungsten or other metal items presented as solid precious metal pieces.
We’ve also discussed the various verification tests that business use to combat these risks, including the scratch and acid test, which is widely used but not very accurate and potentially dangerous. The most precise method is fire assay, but this method destroys the sample – something you do not want to do with a piece of jewelry. Laboratory methods with expensive machines require extensive sample preparation. Finally, there are portable XRF analyzers.
X-ray fluorescence spectroscopy (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. Handheld XRF analyzers work by measuring the fluorescent (or secondary) X-rays emitted from a sample when excited by a primary X-ray source. Each of the elements present in a sample produces a set of characteristic fluorescent X-rays, or “unique fingerprints”. These “fingerprints” are distinct for each element, making handheld XRF analysis an excellent tool for quantitative and qualitative measurements of precious metals, as well as other metals and alloys.
There are different types of portable XRF analyzers, depending on the need. For example, manufacturers may be worried about trace lead in consumer goods, carbon in steel pipes, or metals and alloys used in critical parts, while jewelry manufacturers are concerned about the accurate gold, silver, or platinum content. There are different XRF analyzers that are best for different applications.
How does one know which XRF analyzer is best for the job? We’ve created a chart to compare portable XRF analyzers and used a rating system to show which ones are best for various applications.
Since gold and precious metals are usually in demand this time of year, it is important that jewelry stores and pawn shops have the appropriate tool on hand to verify gold and precious metal content of their pieces – especially since some of these XRF instruments are equipped with proprietary gold-plating detection technology that can alert operators to the probability that an item is plated, regardless of the gold concentration of the plated surface layer. The latest technology works for vermeil (gold-plated silver), as well as gold-plated copper, steel, tungsten and any other non-gold substrate. This is especially useful in the jewelry business.
Another characteristic to take into consideration is how it will be used. Does the operation need an instrument that can sit on a jewelry counter and show the customer that the precious metals content in their piece of jewelry that they are either buying or selling is verified right in front of them?
Take a look at the XRF Analyzer Selection Guide and compare the various portable instruments and their specifications. You’ll quickly find which analyzer is best for your operations. And if you need some help figuring it out, just ask.
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I have a piece of metal that i found 3 feet underground and just with water or was shiny and ice lived here 8 years. I put a torch on it for about 3 min and it finally bubbled a small drop. It never smoked up, just turns red after a long while. It turns into liquid like that guy from the terminator movie, the one that melts into whatever. Ya him. I’ve asked around and people are positive it’s what they say, but it’s been different answers each time, aluminum, iron cast, and some other things. I think it’s in the platinum category. I ordered the acid to try the acid test and it matches up to palladium color or rodium. That would be nice. When i found it, it was in the shape of a nugget. Until i melted it down but it took for ever with a blue propane tank. Stays hot forever too. I just want someone to tell me what it really is and to be sure and proof i guess if what it is. If you guys could help
Platinum has a very high melting point. You won’t melt with propane and air, you would need a gas torch and adjust flame cone to get a blue point (oxidize flame).
We have a pawn shop and need to verify silver, gold, platnum content. Are these tools safe as they emit radiation?
Hi. Thank you for asking. We answered that same question before. Read here: https://www.thermofisher.com/blog/metals/a-readers-question-about-xrf-safety/