VST Fluorescence

What VST Fluorescence Means for Buyers

Fluorescence is how the diamond reacts to UV light. Most commonly a blue glow, but occasionally yellow or other colors. The trade has historically discounted strongly fluorescent stones, especially at the colorless end of the color scale. But for warmer-colored stones (I to M), medium fluorescence can actually make them look whiter in daylight.

Right now we're tracking 22,824 active VST fluorescence listings across our retailer network. The typical natural VST diamond trades around HK$19,066/ct while the lab-grown equivalent sits at HK$13,252/ct. Roughly a 30% gap that reflects the broader natural-vs-lab pricing gap, not a quality difference at this grade.

VST shows up most often in ROUND. About 10,612 listings at this moment. Followed by OVAL. Most of the supply clusters around the 0.5-0.99ct carat range, where demand is strongest and retailers keep the deepest inventory. If you're shopping an unusual shape or carat, expect thinner selection.

The simplest rule: at D to H, avoid Strong or Very Strong fluorescence. It can occasionally give the stone a slightly milky or hazy look in sunlight. At I and below, medium fluorescence is often a bonus that makes the diamond face up whiter. None and Faint are always safe.