Learn About Diamond Fluorescence

Physics - Magnetizing Diamonds with Light

When the term "diamond fluorescence" is mentioned, it might initially evoke thoughts of the gem's radiation. However, in this context, fluorescence is more about how the diamond reflects light and the colour that becomes visible during this process. It can be likened to the intensity of teeth whitening. Is this phenomenon viewed as negative or positive, tacky, or desirable? Continue reading to discover if diamond fluorescence should factor into your purchase decision.

What Is Diamond Fluorescence?

Fluorescence, a form of luminescence or light emission, specifically pertains to whether a diamond exhibits a glow under the shorter wavelengths of ultraviolet light. While ultraviolet light is commonly associated with X-Rays, a relevant scenario here involves the use of a black light. When subjected to this light, a fluorescent diamond absorbs the shorter ultraviolet wavelength and emits a longer one, generating colour due to the excited molecules. In essence, fluorescence enhances the brightness of primary and secondary colours (blue, red, green, yellow, and purple). The intensity of this fluorescence effect varies, with slightly less than a third of diamonds displaying it.

In terms of appearance, here's what can be anticipated from diamond fluorescence:

  • Yellow Diamond = Appears Whiter (considered good as it enhances reflectivity)
  • Colourless Diamond = Appears Bluer (deemed less desirable as it reduces transparency)

Diamond Fluorescence Scale

Imagine fluorescent lighting, which typically emits a glowing, somewhat blue-ish hue. Diamond fluorescence shares similarities with this visual effect. However, its manifestation varies between lower-colour diamonds (J-M colour rating) and higher-colour diamonds (D-F colour rating). Whether fluorescence enhances or diminishes the appearance depends on factors such as the specific diamond, the degree of fluorescence, and individual preferences regarding diamond clarity. If the latter is a significant consideration, it may be worthwhile to request images of the stone under different lighting conditions, given that UV radiation from the sun differs from that of a rave.

Here's an explanation of fluorescence grades:

  • None: No discernible impact on the diamond's colour.
  • Faint: A subtle presence of colour in the diamond, barely noticeable.
  • Medium: A slight hint of fluorescence in the diamond.
  • Strong or Very Strong: Significant and observable fluorescence in the diamond.

Is Diamond Fluorescence Important?

Fluorescence, although technically contributing to the sparkle of jewellery, is not easily perceptible on its own. Faint fluorescence is generally not something you can discern without specialized equipment.

Contrary to the assumption that stronger fluorescence is always better, it's important to note that it doesn't universally enhance a diamond's appeal. While Strong or Very Strong fluorescence might improve the colour grade of yellow-tinted diamonds, it should be carefully balanced. When shopping for diamonds in the D-F or G-H colour range, which already have minimal body colour, excessive fluorescence might overpower them rather than providing a beneficial masking effect. Essentially, colourless diamonds often have a cleaner appearance, and some argue that fluorescence can detract from their purity. Diamonds with compromised colour due to excessive fluorescence are termed "over blues" and may be devalued in the market.

Does Diamond Fluorescence Affect Value?

Certainly, diamond fluorescence can influence how a diamond is perceived, potentially affecting its value. The impact of fluorescence on price varies based on the visual effects it creates for different stones.

For colourless diamonds (D-F) that exhibit fluorescence, especially those closer to yellow light, it is often viewed as a defect, leading to a lower perceived quality. Consequently, colourless fluorescent diamonds tend to be more affordable. On the other hand, for diamonds in the I-M colour range, Medium to Very Strong fluorescence can enhance their value. The blue fluorescence complements the existing yellow undertones, giving the diamonds a higher-quality appearance. In this case, the bluer, the better. This preference for fluorescence becomes more about style than sentiment when determining the value of a diamond.

How Can You Tell If There Is Fluorescence On A Diamond?

Detecting Faint to Medium fluorescence in diamonds is challenging for the average person, as it requires a gemmologist using a UV light source for identification. Even in settings with black lights, such as nightclubs, the quality of the diamond is not easily discernible to the naked eye. According to the GIA, most individuals surveyed actually preferred fluorescence, and its noticeable effect on the stone was limited to cases where it was Strong to Very Strong and the diamond was viewed right-side up. The perceived "oily" or lifeless appearance associated with fluorescence was found to be rare.

In summary, spotting fluorescence in colourless or near-colourless diamonds within the D-J grade ranges, especially when shopping for jewellery online, is a challenging task for the average consumer.

Diamond Fluorescence Shopping Tips

There is no compelling reason to choose or avoid a diamond based on its fluorescence, as its effects are minimal. Whether a diamond exhibits fluorescence or not is more about personal preference and an appreciation for a clear aesthetic rather than a significant impact on the diamond's brilliance. Ultimately, the beauty of the jewellery remains intact, and its value is subjective.

While fluorescence may play a role in the aesthetics of the jewellery, the 4 Cs (cut, colour, clarity, and carat weight) are widely regarded as more reliable indicators of diamond quality and performance.

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