To verify gold authenticity: check the hallmark (999 or 9999 for bullion), run a magnet test (gold is non-magnetic), and confirm the weight against spec. For bars over 10 ounces, XRF plus ultrasound is the complete non-destructive protocol. For silver, weight against spec is the fastest screen. The ice test and ping test add useful at-home confirmation. Neither metal should be trusted on hallmarks alone.

What the Tests Cannot Do

Most at-home tests circulate endlessly — the magnet test, the vinegar test, the skin-discoloration check. They were designed to catch fakes made from cheap base metals. They were never built for the sophisticated counterfeits now in the secondary market.

Gold and silver face different threats. Gold's problem is structural: tungsten is dense enough that scale tests and surface scans can miss it. Silver's problem is easier to solve. Its physical properties are so distinctive that most fakes fail basic at-home tests — if you know which ones to run.

What This Guide Covers

This guide covers both metals end to end. Part One walks through every gold test in order, from hallmarks to professional assay. Part Two does the same for silver. A quick-reference hierarchy at the end lets you find the right protocol for any format.

Why Verification Matters More Than It Used To

Counterfeit precious metals have always existed. What has changed is the sophistication of the fakes and the scale of the market.

Detecting high-grade counterfeit gold bars reliably requires physical testing. Visual inspection and hallmark checks alone catch only a fraction. For silver, the picture is somewhat better. Most silver fakes fail a basic weight-and-dimension check, because no common metal closely matches silver's density. However, silver-plated copper and zinc bars, fake Silver Eagles made with CNC-machined dies, and lead-core bars still circulate in meaningful numbers.

The higher precious metals prices go, the better the economics of counterfeiting become. Therefore, verification is not paranoia. It is standard due diligence for any meaningful allocation to physical metal.

Part One: Verifying Gold Authenticity

Step 1 — Read the Hallmarks

Every legitimate gold product carries stamped markings showing its purity. These are your first checkpoint, not your last.

Understanding karat and fineness marks. Gold purity is expressed two ways. The karat system, common in the United States, uses a number out of 24 — pure gold is 24 karats. The millesimal fineness system, used internationally and on most bullion products, expresses purity in parts per thousand. Both systems map directly to each other.

A bar sold as fine gold should carry a 999 or 9999 stamp. Any other fineness warrants investigation before you complete the purchase.

What a complete bullion bar marking looks like. The LBMA Good Delivery specification is the global standard for wholesale gold bars. It requires four mandatory markings on every legitimate bar: a unique serial number, the refiner's hallmark or logo, the fineness to four significant figures, and the year of manufacture. (LBMA, "Technical Specifications," Good Delivery Rules, January 2026)

Smaller retail bars from accredited refiners like PAMP Suisse, Valcambi, and the Perth Mint follow the same convention. They also include an assay card sealed in tamper-evident packaging. The assay card records the bar's serial number, weight, and fineness at production. When the serial number on the card matches the number stamped on the bar, you have good reason to trust the metal's history.

Step 2 — The Foundational Physical Tests for Gold

These tests require no special equipment. None provide certainty, but each narrows the field.

The magnet test. Gold is non-magnetic. (CRC Handbook) Hold a strong neodymium magnet near any gold item — genuine gold shows zero attraction. This catches fakes made from iron, steel, or other ferrous metals. However, it does not catch copper, brass, tungsten, or any other non-magnetic substitute. Use a rare-earth magnet, not a refrigerator magnet.

The float test. Gold's density is 19.32 g/cm³. (CRC Handbook of Chemistry and Physics, 84th ed.) Drop a bar or coin into water — genuine gold sinks right away. Anything that floats, or sinks slowly, is not solid gold. One important limit: tungsten-core bars are built to match gold's density, so they also sink convincingly.

The ceramic streak test. Drag the item firmly across an unglazed ceramic tile. Real gold leaves a golden-yellow streak. Fakes and plated items leave black or gray. This works well on jewelry and loose coins. However, it cannot be run on a bar still sealed in its assay packaging without voiding the tamper-evident seal.

Skin discoloration. Real gold does not react with skin. Green, black, or blue marks after contact indicate base metals reacting with skin oils. This test is most useful for jewelry and low-karat items. Investment-grade bullion at 999 fineness produces no skin reaction.

Step 3 — Electronic and Professional Testing for Gold

Electronic gold testers. Electronic gold testers measure electrical conductivity. Gold conducts at roughly 70% of copper's rate — a specific signature well below silver but well above base metals like lead or iron. Quality instruments give a fast, non-destructive reading at approximate purity. They are reliable for coins and smaller bars, though less precise on thick or irregularly shaped pieces.

X-ray fluorescence (XRF) scanning. XRF is the standard verification tool at reputable bullion dealers. The instrument fires X-rays at the metal surface. Each element emits a characteristic secondary X-ray signature, producing a non-destructive elemental reading in seconds.

Ultrasound — the solution to the tungsten problem. Ultrasound closes the gap that XRF leaves open. Sound travels through gold at 3,240 m/s and through tungsten at about 5,170–5,180 m/s (CRC Handbook; Evident Scientific, "Material Sound Velocities") — a difference of roughly 60%. Apply an ultrasonic probe to a bar. The sound velocity tells you right away what the bar is made of inside, regardless of what the surface looks like.

Even the most precisely built tungsten-core fake cannot pass ultrasound. This is why it has become the primary counterfeit-detection tool for bulk bullion at the institutional level. The limiting factor is access: professional equipment is expensive and requires trained operators. Most retail investors get it through a dealer or refinery.

The acid test. Jewelers have applied nitric acid to scratched gold for centuries. Genuine gold at 18 karats or higher shows no reaction — acid resistance is one of gold's defining properties. (CRC Handbook) The test is reliable and inexpensive. However, it is slightly destructive, and impractical on bars still sealed in tamper-evident packaging.

Professional assay. For significant purchases — large bars, inherited pieces, or gold from an unfamiliar source — a formal assay by an accredited assayer is the highest level of certainty available. Fire assay dissolves the metal to precisely determine its composition. It is the definitive method. However, it partially consumes the item, so it is not suitable for small coins or condition-sensitive pieces.

The Gold-Specific Counterfeiting Threat: Tungsten

The tungsten-core fake is what makes most at-home gold testing insufficient for larger bars.

Tungsten has a density of 19.25 g/cm³ — nearly identical to gold's 19.32 g/cm³. (CRC Handbook of Chemistry and Physics, 84th ed.) A bar drilled out and filled with a tungsten slug, then resealed with a gold cap, can match the weight and dimensions of a standard 1-kilogram bar. It can pass multiple dealer intake checkpoints. Only a precision density audit at a downstream refiner catches it.

Part Two: Verifying Silver Authenticity

How Silver's Properties Change the Verification Picture

Silver is harder to counterfeit convincingly than gold. The reason is physics.

Gold's problem is tungsten — the one common metal dense enough to fool a scale. Silver has no equivalent problem. Silver's density is 10.49 g/cm³ (CRC Handbook), and nothing common matches it closely enough to pass a precision measurement.

Lead is the nearest candidate at 11.35 g/cm³, roughly 8% denser. That forces a lead-core fake to be smaller in volume to hit the correct weight, so its dimensions give it away. Copper at 8.96 g/cm³ and zinc at 7.13 g/cm³ (CRC Handbook) are both too light to pass at the right size.

Silver also has two physical properties that gold lacks as verification tools: the highest electrical conductivity of any element, and the highest thermal conductivity of any metal — at about 429 W/m·K. (CRC Handbook) Both are testable at home. This gives silver investors more screening options at lower cost — though XRF, ultrasound, and acid testing remain the definitive checks.

Step 1 — Read the Silver Hallmarks

Silver fineness and sterling marks. Silver uses the same millesimal fineness system as gold. Investment-grade bullion bars and coins are stamped 999 (99.9% pure) or 9999 (99.99% pure) — both fine silver. The next most common mark is 925, or sterling silver: 92.5% silver alloyed with 7.5% copper for durability. A stamp of 900 indicates coin silver at 90% purity — the composition of pre-1965 US dimes, quarters, half-dollars, and silver dollars. (US Mint) Continental silver at 800 indicates 80% purity and appears frequently on older European pieces.

Stamps that look like silver but are not. Some markings describe appearance, not content. EPNS (Electroplated Nickel Silver) is silver-plated, not solid silver. "Silver tone" or "silver color" is a finish descriptor with zero silver content. Nickel silver and German silver are copper-nickel-zinc alloys that contain no silver. Alpaca is another name for nickel silver. If any of these appear instead of a fineness number, the piece is not silver.

The assay card and serial number standard. LBMA Good Delivery silver bars carry the same four mandatory markings as gold bars: unique serial number, refiner's hallmark, fineness, and year of manufacture. (LBMA Good Delivery Rules) Retail bars from Valcambi, PAMP, and similar refiners include assay cards pairing the serial number with the bar's specifications. Keep that card intact — a sealed bar with an unbroken assay card from a reputable dealer gives you good reason to trust where the metal has been.

Step 2 — The Foundational Physical Tests for Silver

Silver's physical properties give investors several at-home screening tools that gold simply cannot match.

The magnet test. Silver is not magnetic. (CRC Handbook) Any attraction to a strong neodymium magnet is an immediate fail. This catches low-effort fakes. However, it does not catch lead, copper, zinc, or nickel-silver cores — all of which are non-magnetic.

The weight and dimension check. Because no common metal closely matches silver's density of 10.49 g/cm³, a weight-and-dimension check is more decisive for silver than for gold. A genuine 1 oz fine silver coin or bar weighs exactly 31.103 grams. (US Mint) Any significant deviation is a red flag. A lead-core silver bar is about 8% denser than pure silver. To hit the correct weight, it must be 8% smaller in volume — so its physical dimensions will not match the refiner's published specification. Measuring takes 30 seconds and catches this entire class of fake.

The ice test. Silver has the highest thermal conductivity of any metal, at about 429 W/m·K. (CRC Handbook) Set an ice cube flat on the surface of a silver coin or bar. On genuine silver, the ice melts almost right away — visibly faster than on ceramic, glass, or base metal. Note that copper (about 401 W/m·K) and aluminum (about 237 W/m·K) also conduct heat reasonably well, so a dramatic immediate melt is a strong indicator, not a guarantee. Combine it with the weight check and hallmark inspection.

The ping test. Silver has the highest electrical conductivity of any element. (CRC Handbook) Balance a silver coin on a fingertip, then tap it lightly with another coin. Genuine silver rings clearly at a high pitch and sustains for one to two seconds. Base metals produce a short, dull thud. Drop a pre-1965 US quarter (90% silver) next to a modern clad quarter and the difference is unmistakable. The ping test works best on coins and larger medallions — small items and bars don't ring as clearly.

The tarnish observation. Silver tarnishes as surface metal reacts with airborne sulfur compounds, producing the familiar dark gray or black patina. (CRC Handbook) Silver-plated items over a base metal often tarnish differently, or not at all, because the base metal underneath doesn't react the same way. This is a slow test, but useful for inherited pieces or metal held for years.

The skin discoloration test. Pure silver (999/9999) does not cause skin discoloration. Sterling silver (925) can produce mild discoloration in some people because of the copper content. Base metals like nickel and brass cause faster, more pronounced greening. If a piece sold as fine silver leaves green or black marks on skin, the alloy content is higher than the stamp claims.

Step 3 — Electronic and Professional Testing for Silver

Electronic silver testers. The same electrical conductivity testers used for gold also work for silver. Silver's conductivity is even more pronounced than gold's, giving a distinctive reading. Electronic testers deliver a fast, non-destructive pass/fail and can distinguish between fine silver and sterling silver.

XRF scanning. XRF confirms silver's surface composition and fineness in seconds, non-destructively. The same penetration limit applies as for gold: standard surface XRF reads only about 10 to 20 microns deep. (NIST XCOM Photon Cross Sections Database) A silver-plated lead-core bar passes a surface XRF scan if the plating is thick enough. For any significant bar, combine XRF with the weight-and-dimension check.

The acid test for silver. Silver acid test kits are calibrated for specific purities. Fine silver (999) produces a creamy white reaction. Sterling silver (925) produces a bright red or orange reaction. Base metals turn blue-green or show no reaction. These kits are widely used by dealers and collectors and available at modest cost. However, the surface scratch required makes them unsuitable for coins where condition matters.

Ultrasound testing. For silver bars of 10 oz and above, ultrasound detects lead-tin cores the same way it detects tungsten cores in gold. Sound travels through silver at about 3,650 m/s and through lead at about 2,160 m/s (CRC Handbook; Evident Scientific, "Material Sound Velocities") — silver is roughly 69% faster. A lead-core bar reads as the wrong thickness the moment the probe touches it. This is the institutional-grade check for large silver positions.

Professional assay. Fire assay or cupellation provides definitive silver purity. For large bars or significant inherited holdings where uncertainty remains after other testing, professional assay is the definitive resolution. The caveat is the same as gold: the process partially consumes the item, so it is not suitable for small or condition-sensitive pieces.

The Verification Hierarchy at a Glance

How to Verify Before You Buy

The best verification strategy is upstream. Checking metal you have already paid for is a second line of defense. The first line is buying from a source where the verification has already happened.

Reputable bullion dealers run systematic intake testing on every bar — typically XRF for all formats plus ultrasound for larger pieces. LBMA Good Delivery bars come from accredited refiners subject to ongoing audit. Every bar is traceable by serial number through the chain of custody. (LBMA Good Delivery Rules) Minted coins from sovereign mints are produced to tight specifications with security features that are costly to replicate.

The secondary market — eBay, pawn shops, coin shows, estate sales, private transactions — is where verification matters most. Informally purchased metal has no verified chain of custody. In these cases, run the complete hierarchy: hallmarks and visual inspection first, weight and dimensions second, electronic or XRF third, ultrasound for any large-format bar, and professional assay for anything high-value where doubt remains.

None of this is about fear. The precious metals market is overwhelmingly legitimate. It is about understanding the asset you own — which is precisely what protects your wealth over the long run. For a detailed look at fraud patterns and red flags in both metals, see our guide to spotting fake gold and silver.

Where Verification Meets the Sound Money Thesis

There is a deeper reason to care about this beyond any individual transaction.

Investors hold physical gold and silver — not ETFs, not futures contracts, not paper promises of precious metals exposure — because they want assets outside the financial system. Assets that are exactly what they claim to be. No counterparty risk. No institutional intermediary whose solvency could be questioned.

A gold bar at 99.99% fineness, verified by XRF and ultrasound, confirmed by serial number against the refinery's records — that is as close as a modern investor gets to a genuinely sovereign asset. A silver bar at 99.9% fineness, weight-verified against specification, confirmed clean by XRF, stored with its assay card intact — same principle, different metal.

Knowing how to verify your metals — and knowing your dealer has already done it before they arrived — is part of owning them correctly. That is not paranoia. That is financial sovereignty at its most practical.

For more on how GoldSilver's storage model integrates physical verification with professional custody, see GoldSilver: Home Storage and Vault in One Account.

People Also Ask

How can I test gold authenticity at home?

Start with the hallmark: look for 999 or 9999 on bullion, or 750, 585, or 417 on jewelry. Run a magnet test — gold is non-magnetic, so any attraction is a fail. Confirm weight: a 1 oz fine gold coin weighs 31.1 grams. (US Mint) These three screens catch the majority of low-quality fakes. For reliable confirmation, bring the piece to a reputable dealer for an XRF scan. For bars over 10 ounces, ask specifically about ultrasound — it is the only non-destructive method that detects tungsten-core substitution.

How can I test silver authenticity at home?

Start with weight. A genuine 1 oz silver coin weighs exactly 31.103 grams. (US Mint) Silver's density of 10.49 g/cm³ (CRC Handbook) means most fakes cannot match both the correct weight and the correct dimensions at the same time. Next, run the magnet test — silver is non-magnetic. For coins, use the ping test: balance on a fingertip and tap — genuine silver rings clearly and sustains; base metals produce a dull thud. For bars, try the ice test: silver is the most thermally conductive metal (~429 W/m·K), so it melts ice visibly faster than any base metal.

What does "999" or "9999" mean on gold or silver?

These are millesimal fineness stamps expressing purity in parts per thousand. 999 means 99.9% pure; 9999 means 99.99% — the standard for investment-grade bullion in both metals. (LBMA Good Delivery Rules) For gold, other common stamps include 916 (22K, 91.6%), 750 (18K, 75%), and 585 (14K, 58.5%). For silver, 925 is sterling silver (92.5% silver, 7.5% copper), and 900 is coin silver (90%) — the composition of pre-1965 US circulating coinage. (US Mint)

Can a gold bar pass a weight test and still be fake?

Yes — and this is the most critical fact in gold verification. Tungsten's density is 19.25 g/cm³; gold's is 19.32 g/cm³. (CRC Handbook) That is a difference of less than 0.04% — undetectable by a precision scale. So, a tungsten-core bar passes both the scale test and the float test. Catching it requires XRF plus ultrasound. Sound travels through gold at 3,240 m/s and through tungsten at about 5,170–5,180 m/s (CRC Handbook; Evident Scientific, "Material Sound Velocities") — roughly 60% faster. An ultrasound instrument reads that gap instantly.

Can a silver bar pass a weight test and still be fake?

It is much harder to fool a weight test for silver than for gold. No common metal closely matches silver's density of 10.49 g/cm³. (CRC Handbook) Lead at 11.35 g/cm³ comes closest but is roughly 8% denser. Therefore, a lead-core bar cannot match both the correct weight and the correct dimensions at the same time. Some fakes use a lead-tin alloy core with a thick silver shell to close that density gap. For large silver bars, XRF plus a precise weight-to-dimension check, with ultrasound where available, is the complete verification.

What is XRF testing for precious metals?

XRF fires X-rays at a metal's surface and analyzes the secondary radiation emitted to identify elemental composition — non-destructively, in seconds. The key limitation: standard surface XRF penetrates only about 10–20 microns below the surface. (NIST XCOM Photon Cross Sections Database) A thick enough shell of genuine metal hides whatever is inside. That is why ultrasound is required alongside XRF for any large-format bar.

How do I verify a gold or silver bar's serial number?

LBMA Good Delivery bars carry unique serial numbers assigned by the accredited refiner at production, referenced against inventory records for traceability. (LBMA Good Delivery Rules) The number stamped on the bar should match the number on the assay card exactly. A mismatch — or a missing assay card on a bar that should have one — is a red flag. In that case, seek professional verification before the transaction is completed.