Can a jeweller tell a lab-grown diamond?
Quick answer
Not by eye, and not under a standard loupe. Lab and mined diamonds look identical under normal examination. Telling them apart requires lab equipment, usually spectroscopy or specific fluorescence testing, and many lab diamonds are laser-inscribed on the girdle for confirmation under magnification. The reason it is hard is that they are the same material.
What detection actually requires
The standard tool is DiamondView, which uses short-wave UV light to provoke fluorescence. CVD-grown stones show an orange fluorescence and step-flow striations caused by nitrogen-vacancy centres. HPHT-grown stones show a turquoise fluorescence and blocky growth sectors. Mined diamonds show neither of those patterns. Photoluminescence spectroscopy backs this up by detecting the specific trace defects each growth method leaves behind. Together these are reliable across the full colour and clarity range.
Why a standard diamond tester will not help
Pen-style diamond testers measure thermal or electrical conductivity. Both lab and mined diamonds share those properties, so both pass as "diamond." That is what the tester was designed to do: separate real diamond from simulants like cubic zirconia and moissanite. Lab origin sits outside that test entirely. Most retail jewellers send a stone to IGI or GIA when origin needs to be confirmed.
Next step
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