Pt 34.783 Pd 31.832 Rh 147.893 Au 77.782 Ag 1.009

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Advanced Metal Verification: Eddy Current Testing for Authenticating Gold and Silver

Eddy current testing stands as a non-destructive technique crucial for verifying the authenticity of precious metals. This method, utilizing principles of electromagnetic induction, is essential in fields ranging from quality assurance to counterfeit detection in the metal industry.

Understanding the Eddy Current Method
The method involves inducing eddy currents via a changing magnetic field, generated by an alternating current in a coil. These currents form in the conductive metal under test, creating their own magnetic fields which oppose the original field. The interaction of these fields provides a measure of the metal’s conductivity, primarily assessing surface and near-surface characteristics.

How Eddy Current Testing Works
By measuring the interaction between the coil’s magnetic field and the induced eddy currents, this method evaluates the metal’s conductivity.

Devices like the Sigma Metalytics Precious Metal Verifier (PMV PRO) use this technology to perform swift and accurate authenticity checks on metals. The device’s probe, when placed against a metal item, induces eddy currents and measures the resultant magnetic field reactions, comparing these to known standards for precious metals such as gold and silver.

Application in Metal Authenticity Testing
Eddy current testing is particularly effective in determining the authenticity of precious metals, making it invaluable in environments susceptible to counterfeit risks. The Sigma Metalytics PMV PRO, for example, utilizes this method to confirm if a piece is genuinely made of gold, silver, or another metal, based on established conductivity profiles that differentiate pure metals from their alloys.

Advantages of the Eddy Current Method

  • Non-Destructive: The method does not harm the metal, preserving its integrity.
  • Efficient and Rapid: It provides immediate results, crucial for transactions and evaluations in the precious metals market.
  • User-Friendly: Devices employing this method are designed for ease of use, making advanced testing accessible to a broad audience without requiring specialized knowledge.

Eddy current testing is a sophisticated tool that offers a reliable solution for quickly assessing the electrical conductivity and authenticity of metals. It has become indispensable in the precious metals industry, safeguarding against fraud and ensuring the value of metal items in commerce and collections.


  • National standards for eddy current testing
  • Industry publications on non-destructive testing techniques

Imoprtent Note: Density Measurement

In addition to conducting eddy current tests, the Sigma Metalytics Precious Metal Verifier (PMV PRO) also features the capability to measure the density of metals, an essential factor in verifying authenticity. Accurately determining both the electrical conductivity and density of a metal is critical because these properties can conclusively identify the metal and confirm its purity. The PMV PRO uses this dual-testing approach to provide a comprehensive assessment of the metal, enhancing the reliability of the authentication process. By verifying two distinct characteristics—conductivity and density—the device ensures a robust defense against counterfeiting, reinforcing trust and confidence in the purity and authenticity of precious metals.

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