When examining the alleged cobalt diffusion spinels, GIA researchers discovered high concentrations of nickel, consistent with diffusion treatment.
Nickel treatment has not been noticed or mentioned previously in the gemstone literature. Thus it caused a blue to green color to develop in light spinel. It is also accompanied by artificial healing of cracks resulting from the heating process.
Susan Jacques, president and CEO of GIA said:
“The identification of this new treatment underlines the vital importance of GIA's independent investigation. To protect consumers and ensure that they, and the global gem and jewellery trade, have confidence in their purchases.”.
“This discovery is the result of our very important and comprehensive research programme. In this GIA invests millions of dollars every year.”.
Gems & Gemology, the GIA's quarterly professional journal, recently published the survey online. It will be in the print edition of the magazine in the spring of 2023.
Using advanced spectroscopic equipment, GIA researchers discovered evidence of absorption associated with nickel in natural spinel.
Other key indications of nickel absorption treatment are the concentration of colour at the facet junctions. Photoluminescence spectra indicating heat treatment and unusually high nickel amounts.
