In addition to the so-called 4Cs, there are other criteria that define the nature of the diamond in more detail and determine its value. These criteria are almost never mentioned at traditional jewelers. However, to compare diamonds, all criteria of the diamond are needed. At Yorxs you will receive comprehensive information about your diamond for an informed purchasing decision with maximum transparency.

Whether a diamond exhibits fluorescence can only be determined in the dark and under UV light. The stronger a diamond's fluorescence, the more it glows under UV light. Stones without fluorescence, on the other hand, remain dark. Because sunlight also contains UV light, fluorescent diamonds may appear different in strong sunlight than under artificial light or normal daylight. Fluorescence enhances the color of a diamond.

Fluorescent diamonds are becoming increasingly cheaper and sometimes even significantly cheaper. When it comes to jewelry diamonds, you can take advantage of this price advantage and choose fluorescent diamonds.

For engagement rings and investment diamonds, we always recommend non-fluorescent diamonds!

Fluorescence graduations

None (N) - GIA/ Nil - HRD


No fluorescence, the diamond remains dark under UV light and is 100% light source neutral!

Very Slight (VSL)


Hardly any fluorescence, the diamond remains dark under UV light.

Slight (SL)


Weak fluorescence, the diamond shimmers slightly bluish under UV light.

Faint (F)


Slight fluorescence, the diamond shimmers slightly bluish under UV light.

Medium (M)


Some fluorescence, diamond shimmers bluish under UV light.

Strong (S)


Clearly visible fluorescence, diamond appears blue under UV light.

Very Strong (VS)

Very strong

Strong fluorescence, diamond appears deep blue under UV light.

The fluorescence in detail

The color of fluorescence: The fluorescence of most diamonds is blue. The second most common color of fluorescence is yellow, followed by all other colors of fluorescence. However, these are extremely rare.

The value of the diamond and its fluorescence: Normally, diamonds without fluorescence are much more valuable than those with strong, or even very strong, fluorescence.

The appearance of a diamond with fluorescence: The fluorescence in diamonds means the different reaction of a diamond to unnatural light sources. Because the fluorescence is usually not visible in natural light sources, or in normal lighting, or in daylight. On the contrary, a blue, so-called "blue" fluorescence makes the color of a diamond appear more beautiful and whiter than it actually is. The optical illusion on the human eye is sufficient to make the diamond appear one color level higher because of the fluorescence In particular, the brightness of the brilliance is intensified. The fluorescence only becomes visible to the human eye under a UV lamp, under the so-called white light, only then does the diamond appear, for example, slightly light blue. However, this effect significantly reduces the commercial value of a diamond. You notice this if you change your choice of fluorescence (X1) (from right to left) from N = none, to VSL, SL, F, M = medium, S = strong, or VS = very strong. The diamond prices up to 35% increase (with no fluorescence), or decrease (with very strong fluorescence). As a jewelry diamond, you can buy an otherwise top-rated diamond with fluorescence much cheaper, and in return you will receive a most beautiful wearing diamond. When it comes to an investment diamond, you should strictly avoid fluorescence in order to take advantage of the higher rarity when reselling it to increase its value. And to meet this analytical market trend for investment diamonds.

However, in extremely rare cases, diamonds with very strong fluorescence may appear somewhat milky. This is shown separately as mandatory information for good dealers. Yorxs goes one step further, never delivers these diamonds because our team of experts checks every order. Our sightholders always inform us conscientiously, in accordance with the code of honor of international diamondaires.

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We are available for you from Monday to Friday from 10 a.m. to 6 p.m. and Saturday from 10 a.m. to 3 p.m. Talk to us - we are always happy to help you.