Diamond Basics
How Fluorescence Affects Diamond Pricing
Fluorescence is a cosmetic trait, not a durability or authenticity issue, but it can shift market pricing depending on colour grade and strength.
What the trait is
Fluorescence is the visible glow — usually blue — some diamonds emit under ultraviolet light, caused by trace elements like nitrogen within the crystal. It has no effect on a diamond's hardness or durability.
Market pricing effects
In near-colourless to faint-colour diamonds (G–J range), strong blue fluorescence sometimes trades at a discount because of buyer perception, even though many graders cannot visually distinguish faint fluorescence from none in normal light. In very high colour grades (D–F), strong fluorescence can occasionally cause a hazy or oily look in rare cases.
Reading the report
GIA reports state fluorescence as None, Faint, Medium, Strong or Very Strong. It is worth viewing a strongly fluorescent stone in daylight before buying to check for any haziness.
Buyer checklist
- ✓ Check the fluorescence field on the grading report
- ✓ View strongly fluorescent stones in daylight for haziness
- ✓ Remember fluorescence does not affect durability
Verification tools & references
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