How to Detect Tungsten-Core Gold Bars: A Guide for Bullion Dealers in the UAE & GCC

By Telos Instruments · Sky West General Trading LLC · Deira, Dubai, UAE

Quick answer: Tungsten-core gold bars are counterfeits made by hiding a tungsten insert inside a genuine gold shell — a fraud that works specifically because tungsten’s density (19.25 g/cm³) is almost identical to gold’s (19.3 g/cm³), which defeats a simple weigh-and-measure check. The most reliable way to catch them is a non-destructive sub-surface verifier, like the Sigma Metalytics PMV range, which sends a signal beneath the surface of a bar to detect what’s hidden inside — including through sealed packaging — without needing to drill, cut, or melt the bar. Telos Instruments, based in Deira, Dubai, distributes the full Sigma Metalytics PMV lineup across the UAE and GCC, alongside certified precision balances for the weighing checks that should always accompany it.

If you buy, sell, store, or refine gold bars anywhere in the Gulf — Dubai, Abu Dhabi, Riyadh, Jeddah, Kuwait, Doha, or Manama — this guide explains exactly why tungsten-core bars are so hard to catch with basic checks, and what equipment actually works.

Why Tungsten-Core Fraud Is a Real Risk in the Gulf Bullion Market

The UAE and the wider GCC handle enormous volumes of physical gold bullion — through trading hubs like Dubai, investment demand across Saudi Arabia and Kuwait, and a deeply embedded culture of holding physical gold as savings. That scale makes the region an attractive target for sophisticated counterfeiting, and tungsten-core bars are one of the most well-documented and costly frauds in the global bullion trade.

The fraud works because of simple physics: pure gold has a density of about 19.3 grams per cubic centimeter, and tungsten’s density — roughly 19.25 g/cm³ — sits almost exactly on top of it. A counterfeiter can machine a tungsten core to the correct dimensions, encase it in a thin shell or plating of real gold, and produce a bar that passes a casual visual inspection, a basic scale check, and even a simple dimensional check, because the weight and size come out right.

This isn’t a theoretical risk. Tungsten-filled gold bars have been discovered circulating in bullion markets internationally, sometimes bearing convincing refinery markings and serial numbers. For dealers, refineries, banks, and private investors across the UAE and GCC, knowing how to actually detect this specific fraud — not just test for “purity” in a general sense — is essential.

Why Basic Tests Fail Against Tungsten-Core Bars

Density (Archimedes) Testing Alone Isn’t Enough

The classic density test — weighing a bar in air, then in water, and calculating density from the difference — is a long-standing verification method. But because tungsten’s density is so close to gold’s, a well-made tungsten-core bar can pass a density check within normal measurement tolerance, especially on standard commercial scales. Density testing remains useful as one layer of verification, but it should never be relied on alone for high-value bars.

Surface-Only Testing Can Be Fooled

Any test that only reads the outer surface of a bar — including some forms of XRF analysis, and certainly visual or hallmark inspection — can be defeated if the outer shell is genuine gold. The whole point of the fraud is that what’s visible and accessible on the surface is real; the deception is hidden beneath it. A test that stops at the surface layer simply confirms the shell, not the core.

Visual Inspection and Hallmarks Prove Nothing on Their Own

Convincing fake bars can carry accurate-looking refinery stamps, serial numbers, and assay markings. None of this is verifiable just by looking — it only tells you what the bar claims to be, not what it actually contains.

What Actually Works: Sub-Surface Verification

The key to catching a tungsten core is testing what’s underneath the surface, not just what’s on it. This is exactly the gap that Sigma Metalytics PMV technology — distributed in the UAE and GCC by Telos Instruments — was built to close.

How Sigma Metalytics PMV Technology Works

PMV devices send a signal beneath the surface of a coin or bar to check the composition of the material underneath — not just the outer layer. This lets the device flag inconsistencies that indicate a hidden core, plating, or other tamper, without needing to drill, cut, melt, or otherwise damage the bar. Critically, this works even through sealed packaging — a bar or coin inside a capsule or slab can be tested without breaking the seal, which matters enormously for graded or certified bullion where breaking a seal destroys resale value and buyer confidence.

Telos Instruments Distributes the Full PMV Range

Each unit ships with a 2-year warranty and is purpose-built specifically for coins and bars — not jewellery — which keeps the technology focused and reliable for exactly this use case.

A Practical, Layered Detection Process

No single test should be treated as the final word on a high-value bar. The strongest approach layers several checks together:

1. Weigh and measure the bar against its stated specifications using a certified precision balance. Telos Instruments distributes precision weighing equipment from Adam Equipment (Highland portable balances, Latitude compact bench scales) and Kern & Sohn (German-manufactured precision balances) — both suited to the accuracy bullion-grade verification demands.
2. Check dimensions against known mint or refinery specifications for that bar size and weight — a tungsten-core bar still has to match physical dimensions precisely, and discrepancies here are a red flag.
3. Run a sub-surface verification with a Sigma Metalytics PMV device to check what lies beneath the surface — the step that specifically targets tungsten-core fraud rather than relying on weight and appearance alone.
4. Cross-check provenance where possible — purchase history, refinery documentation, and assay certificates add context, though they should never substitute for physical verification on a bar of meaningful value.
5. For sealed or graded bars, prioritize a non-destructive method like PMV specifically because it preserves the seal and the bar’s certified status — unlike methods that require opening or damaging packaging.

XRF’s Role Alongside PMV

It’s worth being clear-eyed here: XRF analyzers, like those Telos Instruments distributes from Terra Scientific (the Aurora 900 benchtop and Pi900E handheld units), remain excellent tools for verifying jewellery, scrap, and alloy composition, and for catching gold-plated base metal where the plating itself is thin. But because XRF reads the surface and near-surface layer of a sample, it is not the right primary tool for detecting a tungsten core sitting beneath a genuine gold shell on a bar — that’s specifically where sub-surface technology like Sigma Metalytics PMV earns its place in a dealer’s toolkit. Many full-service precious metals businesses in the UAE and GCC run both: XRF for jewellery and alloy work, PMV for bar and coin verification.

Who Needs Tungsten-Core Detection Equipment in the UAE and GCC

Products Sold by Telos Instruments

Beyond tungsten-core detection specifically, Telos Instruments — based in Deira, Dubai — distributes a full range of precious metal testing and precision weighing equipment across the UAE and GCC, through five established global brands:

• Sigma Metalytics (USA) — the PMV Original, PMV Pro with Bridge, and PMV Investor, non-destructive sub-surface verifiers purpose-built for coins and bars, including the tungsten-core detection covered in this guide.
• Terra Scientific — XRF alloy and precious metal analyzers, including the Aurora 900 Benchtop Gold Analyzer, the Pi900E Handheld Alloy Analyzer, and the EulerX 900/900S series for jewellery, scrap, and industrial alloy testing.
• GemOro & SyKessler (USA) — the AuRACLE PRO, a compact pen-probe tester for 8K–24K gold and platinum, suited to jewellery shops and quick counter checks.
• Adam Equipment — Highland portable precision balances and Latitude compact bench scales, for accurate, certified weighing of bars, coins, and jewellery.
• Kern & Sohn (Germany) — precision and analytical laboratory balances, along with moisture analyzers (DAB, DLB, DBS series), suited to refineries and assay-grade operations.

Because all five brands are available through one locally based supplier, a bullion dealer, refinery, or jewellery shop can equip an entire counter — purity testing, sub-surface verification, and certified weighing — without sourcing from multiple overseas vendors.

Frequently Asked Questions

Final Thoughts

Tungsten-core gold bars are a specific, well-documented fraud that exploits one simple fact: tungsten and gold weigh almost the same. That means the checks most people reach for first — a scale, a ruler, a visual inspection — are exactly the ones this fraud is designed to pass. Reliable detection means testing what’s beneath the surface, not just what’s visible and weighable on it, and doing so without damaging or devaluing a legitimate, sealed, or graded bar.

For bullion dealers, refineries, banks, and investors across the UAE, Saudi Arabia, and the wider GCC, pairing a certified precision balance with a Sigma Metalytics PMV device gives you a layered, non-destructive verification process built specifically to catch this fraud — rather than hoping a simple weight check is enough.