When you place a real diamond underneath an ultraviolet light, the stone with fluorescence in it will turn blue. But it's important to know that this will only happen with about one-third of all diamonds. A fake diamond, on the other hand, will almost never look blue under a black or UV light.
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.
Usually fluorescence is blue in color. Less often, a diamond can have yellow or even white fluorescence (other colors too). Diamonds with Strong - or Very Strong - fluorescence can appear quite cloudy, milky or hazy to the naked eye, and emit a prominent and saturated glow in the presence of UV light.
The phenomenon that causes a diamond to glow under black light is called fluorescence. Around 35% of diamonds grown naturally have this component in them, and 95% of them glow a bluish color when exposed to a black light.
Fluorescence occurs in some diamonds when they are exposed to the concentrated radiation of a UV lamp. Submicroscopic structures in the diamonds cause them to emit a visible light, a fluorescence, which is commonly blue in colour.
Fluorescence is the visible light that a diamond emits when it is exposed to the UV rays. Fluorescence is naturally occurring, and at it's best it can make off white diamonds look whiter or more colourless. Around 30% of diamonds evaluated by the GIA have varying degrees of fluorescence detailed on the certificate.
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 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.
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.
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.
An ideal cut diamond shows only a few intensely bright flashes in direct sunlight. A diamond that actually looks good in sunlight splits those few flashes up into ten or twenty smaller sparkles.
You will see that the diamond has white or silvery sparkles only. However, cubic zirconia will give out colourful sparkles such as red, yellow or blue. Another important differentiating feature between these two stones is that a diamond possesses sharp facets, whereas a zirconium does not have sharp facets.
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.
Fluorescent test using a regular UV light source will help to distinguish Natural Diamond vs CZ. Cubic Zirconia will not fluoresce unlike Natural Diamonds Fluoresce of about 25% to 30%.
Simulated diamonds are also known as diamond simulants and include things like cubic zirconia (CZ), moissanite, and YAG. They can also include some natural clear gemstones like white sapphire, white zircon or even clear quartz.
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.
Precious jewellery should not be exposed to concentrated UV light as this could alter the colour and structure of your gemstones. We advise removing jewellery containing gemstones before UV exposure, i.e. nail lamps or sunbeds.
Fluorescence: Sapphires of any color can fluoresce under long wave UV light if iron content is low enough that it doesn't quench fluorescence. Fluorescence colors include pink and red (due to chromium) and orange (due to F-centers or crystal lattice defects according to Vigier & Fritsch, 2023).
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.
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.
You will see a glow in 30% of diamonds under a UV light. When exposed to UV light, there will be a diamond glowing in different colors. 99% of the time, the glow is blue, but on rare occasions, diamonds glow white, yellow, green, or even red in color.
A diamond that has not been cleaned for a while can look milky due to a buildup of film and dirt on its facets. Cloudy diamonds can also have diminished transparency from inclusions or other characteristics intrinsic to the crystal from which they are cut.