Can XRF Technology Produce Accurate Analysis on a Coin in a Holder

Can XRF Technology Produce Accurate Analysis on a Coin in a Holder?

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We recently received an inquiry via our Facebook page about encapsulated coins. The viewer wanted to know if precious metal analysers could analyse coins without removing them from their plastic covering.

Valuable coins are often protected by thin foils or encapsulated in plastic slabs. This is done in order to retain the coin’s value; removing the coin from its protective cover diminishes its value instantly.  It’s like driving a brand new car out of the dealership minutes after the purchase; the car’s value drops as soon as it leaves the dealership. Counterfeiters will often take advantage of this and enclose a fake coin in a protective sheet, assuming and hoping that the buyer is not likely to open it.

Quite a while ago we wrote about a pawnbroker who warned that he “got burned” on two fake silver coins, which amounted to a loss of $4,000. A skilled and experienced pawnbroker, he was still fooled because “All looked good, they had sealed Professional Coin Grading Services (PCGS) holders as well as holograms, they weighed properly, and their numbers matched the  PCGS website. Even scanning the bar code gave the correct number.”  Since PCGS is reputable in third-party certification, he sent the first coin to them for regrading after it defaulted.  Unfortunately, the pawnbroker was informed that not only was the coin a counterfeit, but the holder was fake as well.

He took the second coin to a refiner who used an analyser that utilised X-Ray Fluorescence (XRF) technology on it while it was still in the holder. XRF analysers provide a fast, accurate, and most importantly, a non-destructive method to test the purity and composition of all precious metals. XRF quickly provides the exact karat weight and percentages of all elements within an item – easily identifying non-standard, under-karated, and even advanced counterfeit material.  Unfortunately, this time the refiner found the coin was not made of silver, but instead it was alloyed from lead and nickel.

Many different counterfeit PCGS and NCG slabs (encapsulated coins) – with varying years and conditions – are being sold on various websites.  Buyers must be aware. Even professionals in the numismatic profession have to be on guard.  Sometimes the seller may be aware of the fake, but other times the seller may be selling an item that they thought was real, and probably paid for what they thought was a valuable coin. If pawnbrokers, numismatics, and precious metals dealers are buying and selling coins – with or without holders – it is a good idea to invest in a portable XRF analyser.

Portable XRF technology can easily detect the true composition of the coin by testing through thin foil covers, and provide a very good indication of the coin’s composition even in the case of thicker plastic slabs.

We measured a silver coin twice using our precious metal analyser, once through a protective foil, and once without the foil, showed the following result.

ElementWithout Plastic FoilWith Plastic Foil
Ag88.3 ± 1.187.4 ± 1.1
Cu11.7 ± 0.412.5 ± 0.4

Just a few seconds is all it took to measure the exact precious metal content the coins.  This analyser has a standard analytical range of 21 elements including all precious metals. It is non-destructive; there are no harsh chemicals or acids that can burn your fingers, ruin clothing, damage countertops, or damage the coin. In fact, it is more accurate than those nitric acid test methods. One can precisely determine the presence and concentration of other trace alloying elements and dangerous heavy elements, which could impact valuation.

In addition, coin dealers will frequently examine coins in bulk quantities. The coins are often delivered to the shop in wraps or plastic bags and transactions have to be concluded quickly. Analysing each and every coin by examining its mint year can be a tedious, eye-constraining, distracting, and time-consuming task. With the help of portable XRF analyser, this task can be reduced to a fraction of the time — without having to remove the coins from the wrappers or bags in which they were delivered.

So yes, reader, XRF analysers can ‘see through’ plastic holders and take accurate readings of the metals within. Thank you for your question.  Keep them coming.

Source: Thermo Fisher Scientific – Analyzing Metals

Blog, Coins, Precious Metals, XRF