Authenticating Gold and Silver: Spotting Counterfeits

The vast majority of precious metals transactions are perfectly legitimate. But counterfeits exist — from crude tungsten-filled bars to sophisticated replicas that fool buyers who are not paying attention. Knowing how to authenticate your metals before paying (and after receiving them) is a basic skill every investor should develop.

This guide covers authentication methods from simple home tests that cost nothing to professional-grade techniques used by dealers and refineries. Not every purchase requires all of these steps, but knowing what is available helps you calibrate the right level of scrutiny for the situation.

Why Authentication Matters More for Some Purchases

The risk level varies significantly by where you buy:

• Established online dealers (APMEX, JM Bullion, SD Bullion, etc.) source directly from government mints and approved refineries. The risk of receiving a counterfeit from them is extremely low.
• Local coin shops with long track records also carry very low risk. Professional dealers handle metals daily and spot fakes quickly.
• Private sellers (eBay, Craigslist, Reddit, coin shows) carry meaningfully higher risk. Not all private sellers are fraudsters, but counterfeits circulate most easily in private transactions.
• Too-good-to-be-true prices anywhere should always trigger authentication before you pay.

For standard purchases from reputable dealers, a basic visual inspection and weight check is usually sufficient. For private purchases or unusually priced items, go further.

The Magnet Test (Free, 30 Seconds)

Gold and silver are both non-magnetic. If a coin or bar is attracted to a strong neodymium magnet, it is not genuine precious metal — period. This test instantly reveals iron- or nickel-based counterfeits.

Important caveat: passing the magnet test does not confirm authenticity. Tungsten, one of the most common counterfeit materials (particularly for gold bars), is also non-magnetic. The magnet test rules out low-quality fakes but cannot detect sophisticated ones.

Weight and Dimensions (Free with Proper Tools)

Every legitimate bullion product has published specifications for weight and dimensions. A 1 oz American Gold Eagle weighs exactly 33.93 grams and measures 32.7 mm in diameter. A 1 oz silver bar is typically 50 mm x 28 mm x approximately 3.1 mm.

A precision digital scale (accurate to 0.01 grams, available for under $20) and a digital caliper let you verify that a coin or bar matches its listed specifications. Tungsten is very close to gold in density, which is why sophisticated gold bar fakes use tungsten cores, but silver's density is quite different from common substitute metals, making dimensional checks more conclusive for silver.

Specific Gravity / Density Test

Gold has a specific gravity of 19.3 g/cm³ — one of the densest metals on earth. Tungsten (19.25 g/cm³) is the only common metal that comes close, which is why it is the preferred counterfeiting material for gold. Most other metals are significantly less dense.

You can calculate specific gravity at home using a digital scale with a water displacement setup. This test is more definitive than a simple weight check for detecting tungsten fakes, but it requires some care to execute accurately.

The Ping / Ring Test (Coins Only)

Genuine silver coins produce a distinctive, high-pitched ringing tone when tapped or dropped on a hard surface. This tone results from silver's unique elastic properties. Base metal fakes produce a dull thud.

There are free smartphone apps (the most well-known is Bullion Test) that analyze a coin's acoustic signature. Place the coin on your fingertip, tap it with another coin, and let the app analyze the sound. For standard government coins (American Eagles, Maple Leafs, Philharmonics), this test is very reliable.

Note: this test is primarily effective for coins. Bars have a different acoustic profile and are not well suited to this method.

Visual Inspection Under Magnification

A 10x loupe (jeweler's magnifying glass) lets you inspect strike quality, edge reeding, fine details, and surface characteristics that are difficult to replicate at scale. Legitimate government mint coins have extremely sharp, consistent detail work. Counterfeits often show softness in fine lettering, uneven reeding on coin edges, or subtle discoloration that is hard to see with the naked eye.

Compare what you see against high-resolution reference images from the issuing mint's website. The U.S. Mint, Royal Canadian Mint, and Perth Mint all publish detailed specifications and images for their products.

Acid Testing (Destructive, Definitive for Non-Plated Items)

Acid testing kits are available from most coin supply vendors for $20–$40. The test involves making a small scratch on an inconspicuous area of the coin or bar, applying a drop of nitric acid, and observing the reaction. Different acid formulations test for different metal purities.

Genuine gold will show little to no reaction; base metals react vigorously. For silver, the reaction produces a cream-colored precipitate with genuine metal.

The downside: acid testing leaves a small mark. For collectible or graded coins, this is unacceptable. For bullion bars where you are verifying a large purchase, the cosmetic impact is minor compared to the confidence gained.

XRF Analysis (Professional Standard)

X-ray fluorescence (XRF) analysis uses a handheld device to shoot X-rays at the surface of a metal and analyze the reflected spectrum. It identifies the elemental composition of the top layer of the metal without touching or damaging it. Most professional coin shops and refineries own XRF analyzers.

XRF is the closest thing to definitive surface authentication available without destroying the piece. Its one limitation: it reads only the surface layer, so a tungsten bar with a genuine gold exterior layer will pass XRF. For this reason, XRF is often combined with ultrasonic thickness testing or drilling for large bars.

Ultrasonic Testing (For Bars)

Ultrasonic thickness gauges send sound waves through a bar and measure how the waves bounce back. Because tungsten and gold have different acoustic properties despite similar density, this test can detect a tungsten core inside a gold bar even when XRF shows a clean surface reading. Major dealers and refineries use ultrasonic testing to verify large gold bars before accepting them.

Consumer-grade ultrasonic devices are available for a few hundred dollars. For investors holding significant quantities of large gold bars (100g or larger), this investment can be worthwhile.

Sigma Metalytics Precious Metal Verifier

The Sigma Metalytics Precious Metal Verifier is a mid-range authentication device (around $300–$600) that uses electromagnetic properties to measure metal conductivity in a way that distinguishes genuine silver, gold, and platinum from counterfeits. Unlike XRF, it reads the bulk properties of the metal rather than just the surface, making it effective at detecting tungsten cores in coins.

Many local coin shops own one, and will often verify a coin or bar for a small fee if you ask.

Practical Authentication Checklist

When buying from established dealers, your primary protection is buying from trusted sources in the first place. Learn how to identify a reputable dealer before placing an order.