One simple and popular at-home method to help determine if a diamond is real is the water test. While it is not a definitive or professional assessment, the test relies on a diamond's natural high density, which can set it apart from many common imitations.To perform the water test, fill a clear glass with water at room temperature, about three-quarters full. Then gently drop the loose diamond into the glass. Observe what happens when it enters the water.A real diamond will sink to the bottom due to its high density (approximately 3.5–3.53 grams per cubic centimeter).
Materials like cubic zirconia, glass, or quartz often have lower densities and may float or sink more slowly, depending on their cut and structure. If the stone remains suspended or floats near the surface, it is unlikely to be a real diamond.However, this method is not foolproof. Some simulants can be cut in ways that mimic a diamond’s weight and density, and not all fake stones will float. Additionally, this test cannot differentiate between a natural and a lab-grown diamond, since both are physically identical in terms of density and optical properties.
The water test should only be used as an initial screening tool, especially for consumers with no access to professional equipment. To confirm authenticity, follow up with a diamond tester or take the stone to a certified gemologist for a thorough evaluation using specialized tools and industry-standard methods.In summary, the water test can provide a quick visual indication of whether a stone might be a real diamond, but it should not be used as the sole method for determining authenticity. It is best used in combination with other tests or professional assessment.