The Paraíba
tourmaline controversy
It’s
been more than a decade since the transcendent neon blues
of Brazil’s Paraíba tourmaline first came to market. Like
Tanzanite, Paraíba was named for the area in which it was
mined, a location that has proved to be unique in all the
world. Both of these rare gems have become collectable, and
fine gems of size command princely sums. Traces of copper
and manganese in the molecular structure are responsible
for Paraíba’s stunning color.
Now the term “Paraíba” is
being used to describe other copper-containing tourmalines
from Nigeria and Mozambique, and many in the gem world
aren’t happy about it. These new gems range in color from
shades of robin’s-egg blue to blue-green to green and even
violet. They contain the same ingredients as Paraíba
tourmaline, but in different concentrations. They’re simply
not “Paraíba” in either look or origin, but the sellers of
these stones hope the name’s caché will make their stones
more saleable.
Recently the president of the
American Gem Trade Association (a gem dealer who just
happens to have a large inventory of Mozambique and
Nigerian tourmaline), announced that henceforth the AGTA
gem lab would certify all copper-bearing tourmalines as
“Paraíba”, regardless of origin. He claimed that the AGTA
Board had made the decision, but this proved not to be
true. In the face of outraged opposition, he took a sudden
leave of absence and the AGTA board rescinded the
previously announced policy.
The jury is still out on this
issue, but the most recent issue of Gems and Gemology, the
quarterly journal of the Gemological Institute of America,
reported that probable origin of Paraíba-like tourmaline
could now be determined through sophisticated gemological
testing (LA-ICP-MS, see article at right). The
international Laboratory Manual Harmonization Committee,
which includes seven major gemological laboratories, has
for now agreed to apply the term “Paraíba” to all blue,
bluish-green to greenish blue, green and violet elbaite
tourmaline that contains copper and manganese, regardless
of its origin. But in this country, the FTC forbids using
place names to describe gems unless the seller can provide
documents to support the claim. Stay tuned–and as always,
CAVEAT EMPTOR.
This month’s sources include the article “Paraíba-type
Copper-bearing Tourmaline from Brazil, Nigeria and
Mozambique"; and AGTA member bulletins.