Frequently Asked Questions
What treatments does GIA test for?


Diamonds are tested/examined for laser drilling, glass filling, surface coating, High Pressure/High Temperature (HPHT) processing, and irradiation.
 
Colored gemstones are tested/examined for heating, irradiation, fracture filling/clarity enhancement, coating, dyeing, and diffusion.
 
Pearls are tested/examined for bleaching, heating, dyeing, irradiation, coating, peeling, filling and impregnation.

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