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. However, other imitations, including cubic zirconia, will also sink quickly.
The floating test:
For the floating test, you need a loose diamond and a glass of water. If the diamond is real, it will drop to the bottom of the glass due to the high density of the stone. If the diamond is a fake, it will float on the surface of the water.
True diamonds have high density and should quickly sink to the bottom of the glass. Fake diamonds are not as thick, and therefore, more likely to float in water. This test is not always foolproof. Some materials that make up fake diamonds, such as cubic zirconia and moissanite, can sink if they are heavy enough.
The way that diamonds reflect light is unique: the inside of a real diamond should sparkle gray and white while the outside should reflect a rainbow of colors onto other surfaces. A fake diamond, on the other hand, will have rainbow colors that you can see inside the diamond as well.
Because loose diamonds are so dense, they should sink to the bottom when dropped in a glass of water. Many diamond fakes – glass and quartz included – will float or not sink as quickly because they're less dense.
Categories of Engagement Rings
The second category is known as floating diamond rings. It features an encircled row of pave-set diamonds that runs along with the entire band of the engagement ring without touching each other, hence floating.
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.
As straightforward as it sounds, fill a glass of water at home to roughly three-quarters full. Separate the stone so that it is loose, and drop it into the water. Diamonds are highly dense and a genuine gem will sink to the bottom – every time. If it hovers to the surface or only partially sinks, then it is a replica.
Although natural diamonds can fluoresce almost any colour, the most common colours seen are blue, yellow and white. Synthetic diamonds exhibit green, yellow-green, yellow, orange and vivid red. Lab-grown diamonds can also exhibit phosphorescence when they glow for a minute or more, even after the UV lamp is turned off.
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.
Water Test
If you have a loose diamond to test, fill a regular glass about ¾ of the way full with water. Gently drop the diamond into the glass. If the diamond sinks to the bottom, it's real. If it floats at the surface or just underneath, it's likely a fake.
By holding a diamond close to a source of light, such as a flashlight, you can tell whether or not it's real. Watch closely for the shimmers of light that shine from the stone. A real diamond will reflect light easily, and provide you with a disco ball or rainbow-like display.
The first step is to check for any inclusion on the stone with your bare eyes. If you're unable to see any inclusions with your bare eyes, then use a magnifying glass of at least 10X magnification to find out if the gemstone contains any inclusions. If you found any, then they are real gemstones.
Fake diamonds do not reflect spectral rays from the beam of the flashlight. This is because a diamond's refractive index is high; it makes the white light entering the diamond split into multiple colors before it exits on the other side of the stone.
While it's true that most diamonds, as products of nature, will have inclusions, it is a myth that diamond imitations, whether they are natural or synthetic, will not have inclusions. Inclusions are the result of a gem's crystal growth process. In fact, inclusions help gemologists identify natural and synthetic gems.
The free 4Cs app for Android is downloadable in English and Simplified Chinese. The GIA app is also available for iOS. A retailer version, designed for use at point of sale, is downloadable for free from GIA's retailer support site www.retailer.gia.edu.
Professional jewelers and gemologists cannot tell the difference between a lab created diamond and a natural one just by looking at it with the naked eye. They will have to use a microscope to look for the tiny differences in its inclusions that indicate how it was formed.
The main device used to determine whether a stone is mined or lab-grown is known as a DiamondView. Produced by the Gemological Institute of America (GIA), the DiamondView uses UV lighting to detect a diamond's fluorescence, which is the diamond's sparkle.
All CVD synthetic Diamonds, regardless of color, are magnetically inert (diamagnetic) and cannot be separated from natural Diamonds by magnetic response.
The most effective way to tell Moissanite apart from a diamond is to use a loupe to look through the top, or the crown, of the jewel at an angle. You will see two slightly blurred lines that indicates a double refraction, an inherent quality of Moissanite. Double refraction is easier to see in some shapes than others.
If the small stones on your diamond engagement ring are between 1 and 2 points (0.01-0.02 carats), it may be appraised at a price range of $300 to $700 per carat. Larger chips or stones at 0.10 carats may result in you being able to get $1000 or more for your jewelry if the diamonds score high on clarity and color.
Diamond professionals use the grading system developed by GIA in the 1950s, which established the use of four important factors to describe and classify diamonds: Clarity, Color, Cut, and Carat Weight. Diamonds can be fashioned into a variety of shapes and still be beautiful. These are known as the 4Cs.
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. However, other imitations, including cubic zirconia, will also sink quickly.
Cubic zirconia holds no intrinsic value. Yes, jewelry made with this gemstone will still go for a price, but unless it is set within solid gold, it is unlikely to do anything but lose value as time goes on.