Vivid blue, green, and purple-to-violet cuprian elbaites, renowned in
the gem trade as “Paraíba” tourmalines, continue to be recovered in
small amounts from northeastern Brazil. Since the initial discovery of
this copper-bearing tourmaline in 1982, production has been sporadic and
has not kept up with the strong market demand. Mining currently takes
place at the original discovery—the Mina da Batalha—and at adjacent
workings near São José da Batalha in Paraíba State. At least two
pegmatite localities (the Mulungu and Alto dos Quintos mines) in
neighboring Rio Grande do Norte State have produced limited quantities
of cuprian elbaites. All of these pegmatites occur within Late
Proterozoic metamorphic rocks of the Equador Formation; the source of
the copper is unknown. Six blue to blue-green elbaites from Mulungu had
lower copper contents (up to 0.69 wt. % CuO) than the brightly colored
Mina da Batalha material reported in the literature.
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