A fake diamond will let the black shine through, and you may even be able to read a word depending on the size of the fake stone. If your diamond is mounted, make sure you can't see through it to the mount itself — that's a very bad sign.
Ultraviolet Light: About 30% of diamonds will glow blue under ultraviolet lights such as black light. Fake diamonds, on the other hand, will glow other colors or not at all.
Most synthetic diamonds look too good to be true all due to their extreme brilliance. Does your stone look really bright with lots of rainbow reflected colors? If so, it's most likely cubic zirconia. Yes, real diamonds are brilliant, but they are much more subtle than synthetics.
A real diamond appears gray and white inside (brilliance) when held to the light and can reflect rainbow colors (fire) onto other surfaces. A fake diamond will display rainbow colors within the stone when held up to light.
Sparkle Test Using Reflectivity
Do you see both bright white shimmers and colorful pops of light? With a real diamond, there should be exceptional brilliance and fire when compared with the relatively dull reflectivity of fake diamonds like a Cubic Zirconia.
Diamonds glow in black lighting due to a phenomenon called fluorescence and roughly 35% of natural diamonds exhibit some degree of this effect. In nature, the presence of certain chemical impurities within the diamond's composition triggers this glowing effect in the presence of an ultraviolet light source.
A dirty stone doesn't sparkle because light simply can't enter the diamond and causes it to appear dull. So, if you notice your diamond jewelry getting cloudier overtime, it's likely due to a dirty surface and there's an easy fix to restore their luster.
First, soak your CZ jewelry in warm water and detergent and let it sit for at least 2 minutes. Then use a soft-bristled toothbrush or a cosmetic brush to scrub the jewelry piece until an even sparkle reappears. Remember to rinse and dry the jewelry piece thoroughly to avoid leaving a cloudy residue on your jewelry.
A fake diamond will have rainbow colors that you can see inside the diamond. “People have a misconception that diamonds sparkle like a rainbow, but they don't,” Hirsch said. “They do sparkle, but it's more of a gray color.
Hold your good piece up to your skin and rub it back and forth. You may also hold it between your hands for a few minutes. If it's real gold, your skin will not react to the metal. If it's fake, you may notice your skin turning green, blue, or black where it's come into contact with the jewelry.
If it's real gold it will not stick to the magnet. (Fun fact: Real gold is not magnetic.) Fake gold, on the other hand, will stick to the magnet. If that necklace leaps to the magnet, your significant other has some explaining to do.
Diamonds that belong to a group called type IIB usually look blue. After they absorb high-energy light like UV light however, type IIB diamonds glow in the dark for a short time. This afterglow refers to the phosphorescence of a diamond which ranges in colour from blue to pink and fiery red, depending on the diamond.
The short answer is yes. About a quarter of all diamonds have some measure of fluorescence; however only a very small portion have so much that it actually impacts the appearance. When the fluorescence is a normal amount, or in most cases, the color appears blue.
Roughly 30% of diamonds contain a certain level of boron, which causes the precious gems to glow when they're exposed to ultra violet, also known as "blacklight." The level of boron present in the diamond determines how much light the diamond will emit when exposed.
Visit A Trusted Jeweler
Many jewelers will appraise your stone free of charge and experts will often be able to tell immediately if your diamond is authentic or not. If your stone came with a certificate, your jeweler should be happy to take a look at it and tell you whether it is from a trustworthy source.
You can also fill a cup or glass with white vinegar, and drop your gold in it, let it soak for 5-8 minutes, take it out and rinse with water. If the metal has changed its color even slightly, then the gold is not pure but if it keeps shining, then the gold is pure.
A diamond disperses heat quickly and also dispels fog from its surface almost instantly. So, all you need to do is breathe on your diamond bracelet until the diamonds fog up. Then, note how long the fog remains on the diamonds. If it disappears in a few seconds, voila; the diamonds are real.
This involves taking the diamond and attempting to scratch a mirror. If it leaves a mark on the mirror, it's a real diamond. However, the quality of false stones like cubic zirconia and moissanite has increased, and many can pass this test due to their durability.
Diamonds are dense and will sink quickly, while certain imitations will sink more slowly. If your gem doesn't immediately sink to the bottom, it's likely a glass or quartz imitation.
On the other hand, raw diamonds are uncut and unpolished. In other words, they have not been altered or tampered with after they were discovered. Raw diamonds look like transparent stones with yellowish or brownish tints. There are some that are colorless but these are rare.
Place the gemstones in a glass of water and watch. If it floats, then it is probably a fake stone. Real diamonds will sink to the bottom of the glass, while cubic zirconia will float to the surface.
There is nothing that can scratch a diamond except another diamond. A mineral like talc, on the other hand, is a 1 on the scale. You could scratch it with any hard material, even your fingernail. Natural talc is one of the softest minerals in the world.