Your diamonds glow under a nail light because of fluorescence, a natural phenomenon where trace elements (like nitrogen) or crystal defects in the diamond absorb energy from the UV light and re-emit it as a visible glow, usually blue, but sometimes yellow or green, which is a common characteristic in about 30% of diamonds.
What causes fluorescence in diamonds? Diamonds with fluorescence glow because they have trace amounts of Aluminum, Boron or Nitrogen in them. However, not all diamonds fluoresce! In a study done by GIA researchers, only about 25% to 35% of 26,000 diamonds had any amount of fluorescence when exposed to UV light.
Real diamonds often glow blue under UV light due to natural diamonds. If there is no blue light or the diamond has a different color, it may not be real.
In most cases fluorescence is simply an identifying characteristic and not a performance characteristic, and is therefore NEITHER good nor bad. In some cases, strong or very strong fluorescence can make a diamond appear cloudy, diminishing its transparency and eye appeal.
Fluorescence happens when certain elements and crystal defects inside a gem get “excited” by ultraviolet rays and respond by glowing in vibrant colors, such as blue, green, or even red. It's like a gemstone's private light show! But fluorescence isn't just beautiful.
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.
Phosphorus-doped diamond (PDD) exhibits excellent properties, making it suitable for a wide range of applications, such as electronic devices and electrodes. Here, we report the first synthesis of PDD by in-liquid microwave plasma CVD (IL-MPCVD) under high-pressure and low-power conditions.
Additionally, the Tiffany Gemological Laboratory will not accept stones exhibiting strong or excessive fluorescence, which, in natural lighting, can give diamonds a milky appearance. At Tiffany, laboratory experts determine the color of each diamond by comparing it to authenticated “master” diamonds.
The main disadvantages of lab-grown diamonds are their lower resale value and investment potential, due to mass production and increasing supply, and a lack of traditional sentimental value for those who prefer naturally formed gems with geological history. They also face market perception gaps, with some still viewing them as less prestigious or "fake," and their production involves significant energy consumption, though environmental benefits compared to mining are debated.
Fluorescent diamonds generally cost 10% to 15% less than diamonds graded “faint” or “none.” That means great value and major savings. Remember: Fluorescence very rarely affects a diamond in any visual way. GIA simply measures it for transparency purposes.
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.
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.
A diamond will become fluorescent if there are traces of the mineral boron present in the earth during the crystallization process. Diamonds can fluoresce in a variety of colours – blue, yellow, green, orange and white – but blue is the most common.
Fluorescence most often affects resale pricing when combined with higher colour grades. In some cases, strong fluorescence may cause a hazy or milky appearance under certain lighting conditions, which can influence buyer perception and lead to pricing adjustments.
FALSE! Gemological Institute of America (GIA) conducted a survey of more than 26,000 diamonds. It found that only 25% to 35% of diamonds have some degree of fluorescence. Out of that percentage, only 10% have enough fluorescence to actually affect the appearance or the brilliance of the diamond.
Gemologists and professional jewelers cannot distinguish between a lab-created diamond and a natural one through the naked eye.
The answer to our central question is clear: yes, wealthy people increasingly buy lab-grown diamonds—and they do so with full awareness and intentionality. This trend reveals something profound about the evolution of luxury itself. Luxury is no longer measured solely by what is rare or what costs the most.
Tell people whatever you want to tell them in the context of the moment. Lab diamonds are diamonds. Some people judge lab diamonds because they are uninformed or because they feel like the rise of lab diamonds “cheapens” the meaning of diamond rings. Some people judge mined diamonds because of ethical concerns.
At the bare minimum, the stone is unlikely to lose any value over time. Lab-grown diamonds, on the other hand, are a relatively newer entry to the market. While they share the same physical and chemical properties as mined diamonds, their infinite supply makes them less rare and, therefore, less valuable.
Tiffany & Co. sued Costco for trademark infringement, alleging that Costco's sale of six-prong diamond rings with tags and signs using the name "Tiffany" (or "Tiffany-style") misled customers into thinking they were buying genuine Tiffany products. Tiffany & Co. argued the rings were counterfeits, while Costco claimed "Tiffany" referred to the generic six-prong setting style. The nearly decade-long legal battle ended in a settlement in 2021, after courts had mixed rulings on the "generic" term issue.
Because inclusions are more visible in diamonds with larger, open facets, you should pick VS1 over VS2 when choosing diamonds in shapes other than round (particularly in step-cut diamonds such as emerald-cut or Asscher cut).
The Aquamarine name comes from the Latin word for seawater and is said to calm waves and keep sailors safe at sea. It is sometimes referred to as a poor man's diamond because of the pale color.
The "3-month ring rule" is an outdated marketing guideline suggesting spending the equivalent of three months' salary on an engagement ring, a concept created by De Beers to boost diamond sales, evolving from earlier one and two-month suggestions. Today, it's widely seen as a myth, with most couples prioritizing personal financial comfort, open communication, and meaningful choices over this arbitrary rule.
All diamonds offered by Costco are natural and untreated.