CHEMICAL COMPOSITION
Table 2 presents chemical analyses for representative
samples of Fazenda Bonfim emeralds. A complete listing
of all analyses, including ions calculated for the microprobe
data, is available in the G&G Data Depository
at gia.edu/gandg. The most important chromophore in
the emeralds was Cr, which averaged 0.32 wt.% Cr2O3
and ranged from 0.16 wt.% in light bluish green samples
to 0.72 wt.% in a medium bluish green stone. Vanadium
concentrations were consistently low, averaging 0.03
wt.% V2O3. The other chromophore was Fe, which
averaged 0.82 wt.% FeO and showed a maximum of
1.04 wt.% FeO.