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What is an Assay in Gold and Silver?

Gold or silver assaying ensures that the coins or bars produced by a sovereign or private mint are of the correct and stated purity and weight. While most bullion bars come with a certificate of authenticity the certificate is worth the paper it is printed on. Unless you conduct a physical assay, you do not know for certain the purity of the bar or coin you are examining. However, sovereign mints like the United States Mint or the Royal Canadian Mint rely on internal assays to ensure that their products meet these standards. These mints guarantee the fineness and purity of the products they strike.  

Fire Assay 

Before gold or silver are assayed, the coin or bar thickness is measured, and the diameter is checked to guarantee that it is measured to the exact millimeter. To assay a coin or bar, a sample of the gold or silver being assayed is taken by either drilling into a bar or shaving a tiny piece off the edge of a coin or bar. A fire assay is one of the most accurate ways to check gold or silver purity. However, when you drill into a bar you destroy the collector’s value.  

XRF Assay 

There is a more modern way of testing the gold and silver purity of a bar or coin: X-ray fluorescence (XRF Assay). This method is non-invasive and does not ruin the integrity and appearance of the bar or coin. When using this process, the coin or bar is irradiated by an X-ray beam to measure the density of the coin or bar. Since the beam can only measure so deep on an object, the XRF method is also important in determining the authenticity of a coin or bar by measuring the thickness and diameter. 

Assays are important to determine the authenticity and composition of a gold or silver coin or bar.  Assaying is an independent verification process that can give buyers more peace of mind. By conducting assays on coins and bars, buyers can be assured of the accuracy and authenticity of their purchases. 

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