Start with Our Diamond Quiz
Flashlight Test
To tell if a diamond is real with a flashlight, observe how the stone refracts light. Shine a flashlight directly at the diamond. A real diamond will reflect white light brilliantly, while a fake stone may not reflect as intensely or at all.
Mirror Test
The mirror test involves placing the stone in front of a mirror to see how it reflects light. Hold the diamond at different angles while facing the mirror. A genuine diamond will scatter light intensely, casting strong reflections.
Water Test
For the water test, fill a glass with water and carefully drop the loose stone in. A real diamond, being denser than most imitations, will sink to the bottom. If the stone floats or stays suspended, it's likely not a diamond.
Black Light (UV Light) Test
When exposed to ultraviolet (UV) light, some diamonds emit a glow called fluorescence. While not definitive, this UV light test can indicate authenticity for diamonds that naturally fluoresce. However, lack of fluorescence doesn't necessarily mean a stone is fake, as some real diamonds don't fluoresce at all.
Sunlight Test
Real diamonds in sunlight exhibit a stunning display of brilliance. Take the gem outside or by a window on a sunny day and observe its reflection. A real diamond will produce bright flashes of white light, accompanied by subtle rainbows.
Setting Test
For diamonds set in jewelry, real diamonds are often mounted in high-quality settings like gold or platinum. Check for a hallmark stamp, such as 14K, 18K, or PT, which indicates valuable metal.
Fog Test
The fog test is based on the heat-conducting properties of diamonds. Breathe very lightly on the diamond, creating a light layer of fog. A real diamond will disperse heat rapidly, so the fog should clear almost immediately. If the fog lingers for more than a second, it's likely an imitation.
Dot Test
The dot test can help distinguish a diamond from glass or cubic zirconia. Draw a small dot on a piece of paper and place the diamond flat on top. Look directly down through the stone. If you see the dot clearly, the stone is likely an imitation. A real diamond's high refractive index will scatter light, making it impossible to see the dot clearly.
How to Tell if a Diamond is Real: Best Professional Tests
While at-home tests can provide helpful insight, the most reliable way to determine if a diamond is real is through professional testing and official certification.
Magnifying Glass (Loupe) Test
A professional jeweler can inspect your diamond using a professional-grade magnifying glass, also known as a loupe. Under 10x magnification, a jeweler will check for natural inclusions or imperfections, which are common in real diamonds (unless it is graded VVS+). They will also assess the stone's facet sharpness and overall appearance.
Weight Test
Diamonds have a specific density, so comparing the stone's weight to a genuine diamond of the same size can help identify fakes. Stones like cubic zirconia tend to weigh more than diamonds of the same size. Jewelers use precision scales to measure the difference, ensuring an accurate assessment.
Diamond Tester
Jewelers use a professional diamond tester tool that tests thermal conductivity to differentiate a real diamond from fakes. Diamonds disperse heat quickly, unlike many imitations. A diamond tester will indicate whether the stone conducts heat in the way a diamond should, offering a highly reliable assessment. It’s important to note that some simulants can test as diamonds depending on the specific tester tool.
Diamond Certificate
The most authoritative way to verify a diamond's authenticity is with a diamond certificate from a reputable gemological laboratory like GIA (Gemological Institute of America). These certificates provide detailed information about the diamond's characteristics and, most importantly, its authenticity.
FAQ
How can you tell real diamonds from simulants?
Distinguishing real diamonds from simulants involves examining several characteristics. Real diamonds reflect light with incredible brilliance, primarily white light with minimal rainbow effects. They sink immediately in water due to their high density. When placed over text, you shouldn't be able to read through a real diamond. Fake diamonds often appear too perfect, lacking the subtle imperfections found in natural stones. They may also feel warmer to the touch, while real diamonds feel cool and conduct heat rapidly.
However, we recommend the final verification of a genuine diamond come from an independent lab or professional jewelry assessment of the gemstone.
How can you tell if diamonds are real without a tester?
Without specialized equipment, you can still assess diamond authenticity through several methods. The water test (real diamonds sink immediately), the fog test (breath condensation disappears instantly), and the newspaper test (you can't read through real diamonds) are all somewhat effective. The sparkle test in natural sunlight reveals a diamond's characteristic white brilliance versus the rainbow effects of many imitations. Check the setting quality and metal markings, as genuine diamonds are rarely set in non-precious metals. While not definitive, these combined tests provide some evidence of authenticity.
How can you tell if a mounted diamond is real?
Evaluating mounted diamonds presents unique challenges but remains possible. Examine the setting quality and look for precious metal hallmarks. Real diamonds in quality settings reflect light primarily as white brilliance rather than rainbow colors. The fog test works well for mounted stone, as breath condensation should clear immediately on real diamonds. Check how the diamond appears under different lighting conditions; genuine diamonds maintain consistent brilliance across various environments.
As always, we recommend testing the diamond with a professional jeweler or lab for reliable verification.
