Where to Get Gold Tested for Authenticity
Verify your gold's authenticity and understand its true purity with insights into reliable testing methods, from home checks to professional assessments.
Verifying the authenticity and purity of gold is an important step for anyone acquiring, holding, or selling precious metals. Understanding the true composition of a gold item provides personal assurance, facilitates informed transactions, and helps establish its financial value. Knowing whether a piece is solid gold or merely plated, and its precise gold content, is fundamental for both buyers and sellers in the precious metals market.
Simple At-Home Tests
Consumers can perform several preliminary checks at home to gain an initial indication of a gold item’s authenticity. These methods are generally non-destructive, relying on gold’s inherent physical properties, though they provide indicative rather than definitive results. They serve as a useful first step before seeking professional evaluation.
A strong magnet offers an initial check. Pure gold is not magnetic; strong attraction suggests significant magnetic base metals like iron or nickel. Some gold alloys may have a weak attraction from small amounts of magnetic metals. Non-magnetic metals like copper or aluminum are also used in fakes, so a lack of attraction does not guarantee authenticity.
The unglazed ceramic plate (streak) test involves rubbing the gold item against an unglazed ceramic surface. A gold streak suggests real gold; a black or gray streak indicates another metal. This test can cause a minor scratch, so perform it discreetly on an inconspicuous area.
The float test uses gold’s density. Real gold is dense and sinks quickly in water. If an item floats or sinks slowly, it is likely not genuine. Many other heavy metals also sink, so this test alone cannot confirm authenticity.
Professional Testing Options
For accurate gold authenticity and purity assessments, professional testing services are available. Reputable jewelers, precious metal dealers, and professional assayers have specialized tools and expertise for thorough evaluations. Pawn shops also offer testing, but consumers should seek a second opinion due to varying expertise.
Acid testing (nitric acid test) involves applying specific acid solutions to a small, often scratched, area of the gold item. Different acid strengths correspond to karat levels, and the reaction indicates purity. This method is accurate but can be slightly destructive to the tested area.
Electronic gold testers non-invasively determine gold purity by measuring electrical conductivity. These devices offer quick results and are used by professionals. While more accurate than home tests, precision can vary, and calibration may be required.
X-ray Fluorescence (XRF) analysis offers high, non-destructive accuracy. XRF machines use X-rays to identify the elemental composition, providing a precise breakdown of gold and other alloys. This technique is suitable for valuable jewelry or investment pieces. XRF testing offers accuracy within 2 to 5 parts per thousand.
Fire assay, also known as cupellation, is the most accurate, though destructive, method. This process involves melting a small gold sample at high temperatures to separate pure gold from other base metals. Fire assay is the industry standard for determining precise gold content, used by refiners and large-scale operations, with accuracy reaching 0.01% or 1 to 10 parts per ten thousand. Consumers selling scrap gold or having large quantities refined may find this method necessary.
Understanding Gold Purity
Gold purity is primarily measured and expressed in two ways: karats and fineness, both indicating the proportion of pure gold within a metal alloy. Understanding these measurements is essential for interpreting any test results and assessing the true value of a gold item.
Karats (K) measure gold purity on a 24-part scale. Pure gold (99.9% or more) is designated as 24K. Because pure gold is soft, it is alloyed with metals like copper, silver, or zinc to increase durability for jewelry. Common karat measurements include 18K (75% pure), 14K (58.3% pure), and 10K (41.7% pure). In the United States, 10K is the lowest purity legally marketed as gold.
Fineness expresses gold purity as parts per thousand. For instance, 24K gold is 999 or 999.9 fineness, indicating 999 or 999.9 parts of pure gold per 1000. An 18K gold item is typically marked 750 fineness, meaning 750 parts of gold per 1000. Similarly, 14K gold is often marked 583 or 585, and 10K gold as 417. Many gold items, especially jewelry, have hallmarks or stamps indicating purity using either the karat system or fineness.