Verifying the authenticity of a diamond is essential, whether you’re purchasing, selling, or simply confirming the value of a piece of jewellery. With the market flooded with alternatives like cubic zirconia (CZ) and lab-created gems, knowing how to ensure your diamond is genuine is key to protecting your investment. This article will guide you through what to expect when asking a jewellery store to test your diamond, exploring available methods and considerations for reliable diamond testing.
Why You May Want to Have a Diamond Tested
There are several scenarios where testing a diamond’s authenticity becomes crucial. The most common situation arises when purchasing a diamond, particularly from unfamiliar sellers or online platforms. Given the prevalence of imitation stones like cubic zirconia or moissanite, testing helps confirm you’re getting what you pay for.
Inherited jewellery, often lacking certification, can also benefit from testing, especially if its value is unknown. This is vital if you’re considering reselling or insuring the item, as knowing its authenticity ensures you receive accurate pricing.
Unfortunately, some buyers fall victim to fraud, unknowingly purchasing a fake diamond. A quick test at a jewellery store can offer peace of mind and ensure the diamond matches its described value.
What to Expect When Visiting a Jewellery Store for Diamond Testing
Many jewellery stores offer diamond testing services, often as part of their standard customer service. If you’re a potential buyer or seller, many jewellers will test your diamond at no charge. Some may charge a small fee if you request a formal appraisal or additional services, but basic testing is generally free.
Jewellers use various methods to test diamonds, ranging from basic to advanced. Most stores will have a jeweller’s loupe, a small magnifying glass used to inspect diamonds for imperfections. Thermal conductivity testers, commonly referred to as diamond testers, are also popular tools for assessing whether a diamond is real. Some higher-end stores may offer advanced services, such as electric conductivity testing or using ultraviolet (UV) light to check fluorescence.
Since not all jewellers use the same equipment or offer the same level of service, it’s a good idea to call ahead and confirm the specific methods they use and whether any fees apply.
Popular In-Store Testing Methods
Loupe Inspection
A jeweller’s loupe is one of the simplest and most common tools used for testing diamonds. The jeweller will examine your diamond under magnification, looking for inclusions—natural imperfections that are common in earth-mined diamonds. In contrast, synthetic or lab-created diamonds often lack these imperfections, appearing flawless under a loupe. However, the absence of inclusions doesn’t necessarily mean your diamond is fake; it could simply be a rare, flawless diamond. For this reason, a loupe inspection is often used alongside other testing methods for more accurate results.
Thermal Conductivity Test
The thermal conductivity test is one of the more reliable methods for verifying diamonds. Diamonds are excellent conductors of heat, meaning they disperse heat quickly, unlike materials such as cubic zirconia. Jewellers often use a handheld device known as a diamond tester to measure this heat dispersion. If the diamond tester confirms rapid heat dissipation, it’s a good indication that the stone is genuine.
However, this test isn’t foolproof. Some diamond alternatives, such as moissanite, can conduct heat similarly to diamonds, meaning they could pass this test. As such, jewellers often perform additional tests to confirm the result.
Electric Conductivity Test
Electric conductivity tests are an excellent way to distinguish between diamonds and other stones like moissanite. Unlike cubic zirconia or other imitations, real diamonds conduct electricity better. Jewellers equipped with electric conductivity testers can use this method to confirm the diamond’s authenticity. However, not all stores offer this service, and it may be more common at high-end jewellers.
UV Light Test
Many natural diamonds emit a blue glow under ultraviolet (UV) light, which is why some jewellers use UV light tests to examine the stone’s fluorescence. Although not all diamonds fluoresce, the test can help identify certain characteristics of the stone. While the UV light test alone isn’t conclusive, it provides additional information when combined with other methods.
In-store testing can offer you a clear picture of whether your diamond is real. However, for more complex cases or definitive results, it might be worth considering professional gemological services.
Can You Expect a Free Service?
When visiting a jewellery store, many jewellers provide complimentary diamond testing, especially if they believe you are a potential buyer or seller. This is often true at independent or smaller, family-owned jewellers, where building relationships with customers is a priority.
In larger cities or more commercial stores, the situation may vary. While basic testing is often free, jewellers may charge a fee for more comprehensive appraisals or when dealing with a large collection of jewellery. Some stores may limit the number of items they will test without charge, especially if you’re not planning to make a purchase.
Pawn shops also offer diamond testing services, often free of charge, as they see it as an opportunity to make a purchase offer. However, the quality and thoroughness of the testing can vary significantly between locations.
If you’re serious about confirming your diamond’s authenticity, always ask in advance what type of testing the store performs and whether there are any associated fees.
What Not to Do When Testing Diamonds
The Scratch Test
A commonly cited method for testing diamonds is the scratch test, where the diamond is dragged across glass or another surface to see if it leaves a scratch. While diamonds are harder than glass, this test is not reliable and can damage a real diamond, especially if it has undergone any treatments. Additionally, modern synthetic stones like cubic zirconia and moissanite are also quite hard and can scratch glass, making this test inconclusive.
The Heat and Water Test
Another popular but risky method is the heat test, where a diamond is heated for 30–40 seconds and then dropped into cold water. The belief is that fake diamonds, such as glass or cubic zirconia, will shatter due to the rapid temperature change, while real diamonds will remain intact. While this may work on some imitations, it can damage real diamonds that have been treated with fracture filling or other enhancements. For this reason, the heat and water test is not recommended.
DIY At-Home Methods
There are several DIY methods for testing diamonds, such as the newspaper test or the fog test, but these should be approached with caution. For instance, the newspaper test involves placing a diamond on a piece of printed text to see if you can read the letters through the stone. A real diamond, due to its refractive properties, should make it difficult to see the text. However, this test is unreliable as it depends on the diamond’s cut and clarity.
Similarly, the fog test involves breathing onto the diamond to see how quickly it disperses the heat from your breath. Real diamonds should disperse the heat almost instantly, while fakes will fog up for a few seconds. However, this test can sometimes be misleading, especially for treated or synthetic diamonds. These methods may work as a preliminary check but are no substitute for professional evaluation.
Should You Buy Your Own Diamond Tester?
If you frequently deal with diamonds or plan to make a significant purchase, investing in a diamond tester might be worth considering. These devices, which can be purchased online for a reasonable price, measure thermal conductivity to determine if a stone is likely to be a diamond. However, entry-level diamond testers only measure heat dispersion and might mistake moissanite for a diamond due to its similar properties.
For more accurate testing, higher-end testers that can also differentiate between diamonds and moissanite are available but tend to be more expensive. If you’re a casual diamond owner, purchasing your own tester may not be necessary, as most jewellery stores and pawn shops provide reliable testing with more advanced tools.
Alternatives to Jewellery Stores: Professional Appraisals and Labs
While many jewellery stores provide reliable diamond testing services, there are instances where a more detailed or formal analysis is necessary. If you need a comprehensive evaluation, such as for insurance purposes or high-value transactions, it may be best to consult a certified gemologist or send your diamond to a professional lab.
Professional Appraisals
Certified gemologists, particularly those accredited by respected institutions like the Gemological Institute of America (GIA) or the American Gem Society (AGS), can offer thorough appraisals. These experts not only verify whether your diamond is authentic, but they also assess the stone’s value based on the Four C’s—cut, carat, clarity, and colour.
Many jewellery stores offer appraisal services, but some charge a fee, especially when paperwork or formal documentation is required. This documentation is essential if you need an appraisal for insurance purposes or to resell the diamond in the future. Professional appraisals also provide peace of mind, as they are backed by recognized gemological expertise and often come with certifications.
Diamond Labs
For a comprehensive and highly accurate evaluation, sending your diamond to a professional gemological lab is another option. Labs like GIA and AGS are renowned for their advanced equipment and expertise in diamond testing. They perform a range of tests to determine if the diamond is natural or synthetic and whether it has undergone any treatments, such as coatings or fracture filling.
In addition to confirming authenticity, these labs provide certificates of authenticity, which are crucial for reselling high-value diamonds or insuring them at their true market value. However, using a lab is generally more expensive and time-consuming than a quick test at a local jewellery store.
What To Avoid When Testing a Diamond
It’s important to avoid certain approaches when testing diamonds, especially if you’re conducting tests at home or without professional equipment. Incorrect methods can lead to misinterpretation or even damage your jewellery. Below are key things to avoid:
Relying on One Test
Testing a diamond with just one method can lead to inaccurate conclusions. For example, while the fog test is useful, it’s not always reliable—especially for treated or synthetic diamonds. Similarly, tests like the newspaper or dot test can give misleading results if the diamond’s cut or clarity is atypical. Always combine multiple tests to get a more accurate assessment of the stone.
Ignoring Professional Advice
When in doubt, it’s always best to consult a professional jeweller or gemologist. They have access to specialized tools and years of experience that provide a level of accuracy that at-home tests cannot match. Relying solely on DIY methods or non-expert opinions may lead you to the wrong conclusion.
Testing Treated Diamonds with At-Home Methods
Some at-home tests, such as the heat and water test, can damage diamonds that have undergone treatments like fracture filling or coating. These treatments are designed to enhance the diamond’s appearance, and exposing the stone to extreme heat or sudden temperature changes can reverse these enhancements or even cause permanent damage.
To avoid damaging your jewellery, always consult a professional if you suspect your diamond has been treated or if you’re unsure about the best testing method to use.
Conclusion
Getting your diamond tested at a jewellery store is often a straightforward and convenient way to confirm its authenticity. Many jewellers offer free or low-cost services, using tools like loupes and thermal conductivity testers to check for common indicators of a real diamond. However, the accuracy and depth of these tests can vary based on the equipment used and the expertise of the jeweller.
For those seeking more detailed assessments, professional appraisals and gemological labs offer advanced testing options, including electric conductivity tests and certification for high-value diamonds. While these services come with higher costs, they provide definitive results, ensuring your diamond’s authenticity and value.
When in doubt, always avoid unreliable testing methods, such as the scratch test or heat and water test, which can damage your diamond or give false results. Instead, consult with professionals who have access to the right tools and knowledge to provide a thorough and reliable evaluation.
By taking these steps, you can ensure that your diamond is genuine and avoid costly mistakes, whether you’re buying, selling, or simply verifying the authenticity of a treasured piece of jewellery.
