Pawn shops use a combination of quick screening methods and more precise scientific tests to determine whether gold is real and how pure it is. Most shops layer several techniques together, starting with simple visual checks and magnets, then moving to acid testing or electronic analyzers for a definitive reading. The specific tools vary by shop, but the goal is always the same: figure out the karat purity so they can calculate what the gold is actually worth.
The Magnet Test: A Quick First Screen
The very first thing many pawnbrokers reach for is a rare earth magnet, which is stronger than a typical refrigerator magnet. Gold has no magnetic properties, so if a piece jumps toward the magnet or you can feel a pull, it’s either fake, gold-plated over a base metal, or contains a significant amount of non-gold material. This test takes seconds and instantly weeds out obvious counterfeits before the shop invests time in more detailed analysis.
There are a few quirks to watch for. Clasps on necklaces and bracelets often contain tiny iron springs that will react to the magnet, and some hollow earrings have a small metal rod inside for structure. A knowledgeable pawnbroker accounts for these and doesn’t reject a piece just because the clasp twitches. The magnet test also can’t confirm that something is gold. Non-magnetic metals like copper and brass won’t react either, so passing the magnet test only means the item moves on to the next round of testing.
Visual Inspection and Hallmarks
Pawnbrokers examine each piece closely, often with a jeweler’s loupe, looking for hallmarks or stamps that indicate gold purity. These are small markings pressed into the metal, typically a number followed by “k” or “kt” (10k, 14k, 18k, 24k) showing the karat rating. A 14k stamp, for example, means the piece is roughly 58.3% pure gold, with the rest being alloy metals that add strength and color.
Hallmarks give the shop a starting point, but they’re never taken at face value. Counterfeit jewelry often carries fake stamps, and older pieces may have worn markings that are hard to read. The pawnbroker also looks for signs of wear that might reveal a different-colored metal underneath, discoloration around edges and clasps, or sloppy construction that suggests a piece isn’t what it claims to be. Visual inspection narrows down what they’re dealing with, but it’s always confirmed by a chemical or electronic test.
The Acid Scratch Test
Acid testing is one of the most common and affordable methods pawn shops use to verify karat purity. The process works like this: the pawnbroker makes a small scratch on an inconspicuous part of the jewelry, rubbing it against a dark testing stone (called a touchstone) to leave a visible streak of metal. Then they apply a drop of acid solution to that streak.
Each acid solution is formulated for a specific karat level. There are separate acids for 10k, 14k, 18k, and 22k gold. If the metal streak dissolves or changes color when exposed to the acid, the gold content is lower than what that acid tests for. If the streak holds steady, the gold is at least that karat level. By working through the acid solutions in order, the shop can zero in on the exact purity.
The scratch is typically tiny and placed where it won’t be noticed, like the inside of a ring band or the back of a pendant. Still, this is a mildly destructive test, which is one reason some shops have moved toward electronic or X-ray alternatives. Acid test kits are inexpensive and widely available, making them the standard in smaller shops that handle a moderate volume of gold transactions.
Electronic Gold Testers
Electronic testers measure the electrical conductivity of a piece to determine its gold content. Different metals and alloys conduct electricity at different rates, so the device can estimate karat purity by reading how the metal responds to a small electrical signal. One of the more popular models in the pawn industry is the GemOro AuRACLE, which can test yellow gold from 6k up to 24k as well as platinum. It calibrates against a known 14k or 18k standard and gives a digital readout within seconds.
For bullion (coins and bars rather than jewelry), some shops use a device called the Sigma Precious Metal Verifier, which costs around $680 and works by measuring conductivity beneath the surface of the item. This is particularly useful because it can detect counterfeits that have a gold exterior over a base-metal core, and it can even read through protective slabs or cases without requiring direct contact with the metal.
Electronic testers are faster and less destructive than acid, but they work best as part of a layered approach. A reading can sometimes be thrown off by heavy plating, unusual alloy combinations, or surface contamination, so most experienced pawnbrokers use electronic results alongside at least one other method.
XRF Analyzers: The Most Precise Option
X-ray fluorescence (XRF) analyzers are the gold standard, if you’ll pardon the pun, for non-destructive precious metal testing. These machines direct a beam of X-rays at the jewelry, which causes the atoms in the metal to emit secondary X-rays at energy levels unique to each element. The analyzer reads those emissions and produces a detailed breakdown of every element present and its exact concentration.
An XRF scan can tell you not just that a ring is 14k gold, but that it contains, say, 58.5% gold, 25% copper, and 16.5% silver. This level of detail makes it nearly impossible to fool. The test takes only seconds, leaves no mark on the jewelry, and works on items of almost any size or shape.
The main reason not every pawn shop has one is cost. Benchtop XRF analyzers run into the tens of thousands of dollars, so they’re more common in higher-volume shops and dedicated precious metal dealers. Handheld models are somewhat less expensive but still a significant investment. If you’re selling a high-value piece and want the most accurate test possible, it’s worth asking whether the shop uses XRF technology.
The Density Test
Gold is unusually dense compared to most metals. Pure 24k gold has a density of about 19.3 grams per cubic centimeter, and even lower-karat alloys are noticeably heavier than common base metals. Some pawnbrokers use a density test as an additional verification step: they weigh the piece precisely on a calibrated scale, then measure its volume (often by submerging it in water and measuring displacement), and divide weight by volume to get the density. If the result falls within the expected range for the claimed karat, that’s strong confirmation.
This test is more common for simple, solid items like bars or coins than for intricate jewelry, since hollow construction, gemstones, or mixed materials can throw off the volume measurement. It’s a useful backup method rather than a primary one.
The Certified Scale
Once the pawn shop has confirmed the gold’s purity, they weigh it on a precision scale to calculate its value. These aren’t ordinary kitchen scales. Pawn shops are required to use legal-for-trade scales that meet standards set by the National Institute of Standards and Technology (NIST). These scales undergo rigorous testing and certification, are sealed at the factory to prevent tampering, and must be accurate down to very small increments (often 0.01 grams or finer). Weights and Measures inspectors can audit these scales to ensure they haven’t been altered.
Gold is traditionally weighed in troy ounces (31.1 grams) or pennyweights (1.555 grams) rather than standard ounces. If a shop quotes you a weight in pennyweights and a price per pennyweight, you can multiply pennyweights by 1.555 to convert to grams, or divide by 20 to get troy ounces. Knowing this helps you compare the offer against current gold spot prices.
What This Means When You’re Selling
When you walk into a pawn shop with gold, expect the process to take just a few minutes. The pawnbroker will likely start with a visual check and magnet, then move to either an acid test or electronic tester depending on what equipment they have. Larger or higher-end shops may run an XRF scan. They’ll weigh the piece on a certified scale and calculate an offer based on the current gold price, the karat purity, and the weight.
You’re within your rights to ask which testing methods a shop uses before agreeing to anything. If a shop relies solely on a magnet and a visual glance, that’s a red flag. Reputable shops use at least two methods and are usually happy to show you the test results. If you have multiple pieces of different karats, each should be tested and weighed separately, since mixing them together would lead to an inaccurate valuation.