elle_chris
Ideal_Rock
- Joined
- Feb 19, 2004
- Messages
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ETA: I see the article was already linked so disregard my post. I mean why bother believing GIA study....
GIA discusses HPHT Colors including Blues in This Article
From
" Most early gem-quality HPHT synthetics were fancy color, since color-causing impurities, such as nitrogen (yellow) or boron (blue), were often prevalent within the growth system. Recent progress in growth technology has allowed for better control of impurity contents, resulting in the creation of colorless crystals"
And
"Most colors of HPHT synthetics are believed to be as-grown (i.e., due to impurities) rather than the product of post-growth treatment processing. In contrast, CVD synthetics are often subjected to post-growth treatment. Most near-colorless CVD synthetics are subsequently HPHT treated (to remove any brown coloration), while the pink samples (the other major CVD product) undergo irradiation and annealing (Eaton-Magaña and Shigley, 2016)."
Also
"Blue HPHT synthetics result from the presence of boron within the growth chamber. Colorless HPHT synthetics are reportedly sold as-grown without post-growth color modification (D’Haenens-Johansson et al., 2014), and they often contain small amounts of boron, which does not alter their color (but does impart luminescence)."

GIA discusses HPHT Colors including Blues in This Article
From
Observations on HPHT-Grown Synthetic Diamonds: A Review
" Most early gem-quality HPHT synthetics were fancy color, since color-causing impurities, such as nitrogen (yellow) or boron (blue), were often prevalent within the growth system. Recent progress in growth technology has allowed for better control of impurity contents, resulting in the creation of colorless crystals"
And
"Most colors of HPHT synthetics are believed to be as-grown (i.e., due to impurities) rather than the product of post-growth treatment processing. In contrast, CVD synthetics are often subjected to post-growth treatment. Most near-colorless CVD synthetics are subsequently HPHT treated (to remove any brown coloration), while the pink samples (the other major CVD product) undergo irradiation and annealing (Eaton-Magaña and Shigley, 2016)."
Also
"Blue HPHT synthetics result from the presence of boron within the growth chamber. Colorless HPHT synthetics are reportedly sold as-grown without post-growth color modification (D’Haenens-Johansson et al., 2014), and they often contain small amounts of boron, which does not alter their color (but does impart luminescence)."
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