Identifying and recognizing the different hallmarks is one of the first pieces of advice given to someone seeking an initial appraisal of a piece of gold jewelry. These hallmarks distinguish between the different fine gold contents of jewelry, expressed in carats or thousandths. But how do you know if a piece of jewelry is gold if there is no hallmark? There are several techniques that can be used to distinguish gold from other precious and non-precious materials when the hallmarks are altered or missing.
Gold and its properties
The methods used to identify gold jewelry are based on the physical and chemical properties of gold. Precious metal is distinguished by several specific characteristics:
• Its softness
• Its non-magnetic nature
• Its high density
• Its heat resistance
• Its conductivity
Various tests to perform at home
Certain tests are easily performed by individuals to distinguish gold from gold-plating, as well as white gold from silver.
Gold is a particularly soft metal, which is why it is not used pure in jewelry. This softness can be verified by performing the so-called "bite test," which is supposed to leave traces in jewelry made from a fine gold alloy. It's also possible to scratch the ring or the second hand bracelet to be appraised on a ceramic surface: a yellow mark indicates the presence of gold, while a black mark reveals another alloy. But be careful with these tests; they are approximate and can damage the jewelry.
Using a powerful magnet also allows you to check whether your jewelry is primarily made of gold. If the jewelry isn't magnetic, it may be gold. If it attracts the magnet, it's likely plated.
Finally, the density of a piece of gold jewelry can be tested by weighing the item and then submerging it in water to assess the ratio between its mass and the volume of water displaced. Each carat has a specific gravity range. For example, between 15.2 and 16.9 g/ml for 18-carat yellow gold.
Various tests performed by professionals
Some tests require special expertise, but also the use of chemicals or manipulations that could damage the jewelry if performed incorrectly. They must therefore be entrusted to professionals.
All tests involving acidic substances (nitric acid) or testing the thermal resistance of gold should therefore be reserved for professional appraisals of antique jewelry.
Precious metals professionals can also run the jewelry through a spectrometer. This expensive device provides a detailed view of the jewelry's materials and indicates its fine gold concentration. This is one of the methods that can be used in workshops to estimate the value of a vintage ring based on its carats, without risk of alteration.
How to Avoid Counterfeits
The price of the precious yellow metal is constantly rising, and selling your gold is a common way to raise cash. In a market with a growing number of players, counterfeiters are also competing with each other to attract and deceive buyers. Knowing how to recognize real gold helps protect yourself, in part, against fraud attempts.
Several techniques can be used to identify counterfeit antique or designer jewelry, including observing the clasp, which is often different from those used by the brand.
The safest way to avoid counterfeits is to choose a reliable and reputable seller, such as a jewelry store specializing in antique jewelry and the sale and purchase of gold. They will issue you a certificate of authenticity with the jewelry.
Myths About Gold Testing
Some tests can provide clues about the authenticity of a piece of jewelry, but they don't guarantee that it is indeed gold. This is the case with the magnetic test: other precious metals, such as silver, are also non-magnetic. The test is therefore not enough to distinguish white gold from silver.
Signs of wear are also not always easy to interpret when you don't have an expert eye. Depending on the alloy's carat weight, the gold jewelry will be more or less soft and therefore wear differently.
Contrary to popular belief, the color of gold is not an indicator of purity: this can be influenced by the materials present in the alloy.
Finally, remember that the absence of a hallmark does not definitively mean that the jewelry is not gold: on antique jewelry, particularly rings worn daily, the hallmarks may have disappeared through prolonged contact with the skin.
Having a professional appraisal is the most reliable method for authenticating 18-karat gold jewelry without risking altering it. Gemme Jewelry stores performs a complete appraisal of your jewelry, which takes into account the gold content and the value of the stones, as well as the jewelry's quality, aesthetics, rarity, and history.
