HRD An­twerp: Flu­o­res­cence Has Pos­i­tive In­flu­ence On Di­a­mond Colour

Solitaire - - SPECTRUM -

HRD An­twerp, a lead­ing Euro­pean author­ity in di­a­mond cer­ti­fi­ca­tion, re­cently un­der­took a study en­ti­tled “The ef­fect of flu­o­res­cence on the colour of a di­a­mond”, con­clud­ing that even strong flu­o­res­cence does not neg­a­tively im­pact a di­a­mond’s ap­pear­ance.

In fact, their find­ings demon­strate the con­trary: un­der nor­mal con­di­tions and even when out­doors, strong flu­o­res­cence has a pos­i­tive in­flu­ence on the colour of di­a­monds.

This find­ing di­rectly con­tra­dicts the com­mon per­cep­tion that flu­o­res­cence is a neg­a­tive prop­erty of di­a­monds, driv­ing down their value. Given HRD An­twerp’s find­ings, they con­clude there is no jus­ti­fi­ca­tion for the price penal­ties that cur­rently ap­ply to flu­o­res­cent di­a­monds.

To make this de­ter­mi­na­tion, the grad­ing and cer­ti­fi­ca­tion lab wanted to iden­tify how flu­o­res­cence in­flu­ences the colour grad­ing re­sults of di­a­mond ex­perts and gem­mol­o­gists in stan­dard­ised lab­o­ra­tory en­vi­ron­ments, as well as to as­sess how flu­o­res­cence in­flu­ences the vis­ual ap­pear­ance of a di­a­mond for reg­u­lar con­sumers. The lat­ter was the main pur­pose of the study: to de­ter­mine the im­pact on the ap­pear­ance of a mounted di­a­mond as ob­served by an end con­sumer.

The ex­per­i­ments HRD An­twerp con­ducted in its lab­o­ra­tory re­vealed sev­eral sig­nif­i­cant points, fore­most of which is that di­a­mond flu­o­res­cence has no in­flu­ence on the colour grad­ing of a di­a­mond in a lab­o­ra­tory en­vi­ron­ment, due to the in­signif­i­cant UV con­tent in con­ven­tional grad­ing lamps. In short, flu­o­res­cence should not lower the of­fi­cial colour grade. Fur­ther­more, con­ven­tional grad­ing through the pavil­ion (lower half) of a di­a­mond in out­door con­di­tions ac­tu­ally im­proves the colour grade for di­a­monds with a flu­o­res­cence grade above ‘medium’.

As an ex­am­ple, a di­a­mond graded in the HRD An­twerp lab­o­ra­tory as a J colour with very strong flu­o­res­cence can ap­pear as a D colour when ex­am­ined in out­door con­di­tions. When the di­a­mond is ex­am­ined through the ta­ble (face up), there is still an improve­ment in colour, al­though this change is less sig­nif­i­cant.

The re­sults of HRD An­twerp’s study thus sup­port find­ings from ear­lier stud­ies con­ducted by other labs, adding ad­di­tional ob­jec­tive as­sess­ments. It con­firms that even very strong flu­o­res­cence has no detri­men­tal ef­fect on the ap­pear­ance of di­a­monds in a lab­o­ra­tory set­ting, and when viewed through the pavil­ion in out­door con­di­tions, it re­sults in a clear improve­ment in a di­a­mond’s colour. For the wearer or ca­sual ob­server, flu­o­res­cence has a neu­tral or even pos­i­tive im­pact on the ap­pear­ance of a di­a­mond, mak­ing it ap­pear to be more colour­less. Given these ob­ser­va­tions, HRD An­twerp con­cludes there are no grounds on which to jus­tify the price penal­ties that cur­rently ap­ply to flu­o­res­cent di­a­monds.

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