When you walk into a coin shop or precious metals dealer to sell gold or silver, the first question on your mind is simple: how do they know what my item is actually made of? The answer, at the best dealers, is X-ray fluorescence analysis — commonly known as XRF testing. It is one of the most important advances in precious metals evaluation, and understanding how it works can help you get a fair deal every time you sell.
How XRF Works
XRF analysis works by directing a focused beam of X-rays at the surface of a metal object. When the X-rays hit the atoms in the metal, they cause those atoms to emit their own characteristic fluorescent X-rays. Each element — gold, silver, platinum, copper, nickel, zinc, and so on — emits X-rays at a unique energy level, like a fingerprint. The XRF device reads those energy signatures and calculates exactly what elements are present and in what percentages.
The result is a detailed composition report that tells the dealer precisely what your item is made of. A gold ring that looks like 14K can be confirmed as 14K — or revealed as 10K, 18K, or even gold-plated base metal. There is no guessing involved.
Why It Matters for Sellers
Before XRF technology became widely available, dealers relied on acid testing to determine gold purity. Acid testing involves scratching the item on a testing stone, then applying different strengths of acid to see which one dissolves the streak. While this method works, it has significant limitations. It only tests the surface — which means a gold-plated item can sometimes fool an acid test. It requires physical contact with the item, which can leave marks. And it provides an approximate range rather than an exact measurement.
XRF testing eliminates all of those problems. It is non-destructive — the item is not scratched, marked, or damaged in any way. It tests the actual composition throughout the material, not just the surface layer. And it provides exact percentages down to the decimal point.
For sellers, this means two things. First, you can trust that the assessment is accurate. Second, a more accurate assessment typically means a higher payout, because the dealer is not building a safety margin into their offer to account for uncertainty.
What XRF Can Test
XRF analysis works on virtually any metal item. Gold and silver jewelry, coins, bars, rounds, dental gold, platinum pieces, and even industrial scrap can all be tested. At CoinBox Gold & Silver in Fountain Inn, SC, the XRF equipment can identify the composition and percentage of 26 different elements, providing a comprehensive picture of exactly what a piece contains.
This is particularly valuable for unusual or unmarked items. Antique jewelry may not have a karat stamp. Foreign coins may be unfamiliar. Bars or rounds from lesser-known mints may need verification. XRF provides answers in seconds without any guesswork.
What XRF Cannot Do
It is worth noting that XRF testing has some limitations. It tests the composition of the material but does not determine numismatic value — that requires human expertise in grading, rarity, and market demand. A coin might be confirmed as 90% silver by XRF, but whether it is a common date worth $30 or a key date worth $3,000 depends on knowledge that no machine can provide. The best dealers combine XRF technology with numismatic expertise to evaluate items from both angles.
How to Know If Your Dealer Uses XRF
Simply ask. Any dealer who has invested in XRF equipment will be happy to tell you about it — it is a significant capital investment that demonstrates their commitment to accuracy and transparency. If a dealer is still relying solely on acid tests or visual inspection, that does not necessarily mean they are dishonest, but it does mean their assessments carry more uncertainty. And uncertainty usually means lower offers.
The Takeaway
When selling gold, silver, or any precious metal, the accuracy of the assessment directly impacts the price you receive. XRF testing is the gold standard — no pun intended — for metal analysis, and choosing a dealer who uses it is one of the simplest ways to protect yourself and maximize your payout.
In the Greenville, SC area, CoinBox Gold & Silver in Fountain Inn uses state-of-the-art XRF analysis on every item they evaluate. You can visit them at 309 S. Main Street, call (864) 692-1100, or learn more at coinboxusa.com/. Knowing that your items are being tested with the best available technology gives you confidence that the offer you receive reflects the true value of what you are selling.