Cuprian Elbaite - The Mineralogical Record

136
Figure 15. Cuprian elbaite scepter crystal, 2 cm,
from the Batalha mine. Michael Scott collection;
Van Pelt photo courtesy of Michael Scott.
Finally, it should be noted as a warning that some marketers
have been offering blue-to-green copper-free tourmaline as Paraíba
tourmaline in order to obtain a much higher price
CONCLUSIONS
Although the area in northeastern Brazil where occurrences of
cuprian elbaite have been found is fairly large, none of the
localities has produced crystals equal to those found at the Batalha
mine. Furthermore, almost all good crystals of any size tend to be
shattered, and the remainder are generally embedded, non-gemmy
and not of good collector quality. As long as mining continues in
the area, the possibility of more good crystals being found exists,
but their extremely high gem value probably means that most will
continue to be cut as gemstones rather than saved as crystal
Figure 17 . Cuprian elbaite crystal section,
1.5 cm, turquoise-blue with purple core, from
the Batalha mine (ca. 1989). Brian Cook specimen;
Wendell Wilson photo.
Figure 16. Faceted cuprian elbaites showing a
range of color. Michael Scott collection; Van
Pelt photo courtesy of Michael Scott.
specimens. Consequently, even very small crystals of good color,
form and transparency will probably remain very rare in collections
and on the market.
ACKNOWLEDGMENTS
I am grateful to Brendan Laurs and James Shigley (Gemological
Institute of America) and Anthony Kampf (Natural History Museum
of Los Angeles County) for reviewing the manuscript, and
for graciously providing information and photos. Brian Cook
(Nature’s Geometry) also provided information and loaned specimens
for photography.
BIBLIOGRAPHY
ADUSUMILLI, M. S., CASTRO, C., and BHASKARA RAO, A.
(1994) Blue and green gem tourmaline from Gregório pegmatite,
Rio Grande do Norte State. In: 16th General Meeting of the
International Mineralogical Association, Pisa, Italy, 1–13.
ALMEIDA, F. F. M., HASUI, Y., BRITO NEVES, B. B., AND
FUCK, R. A. (1981) Brazilian structural provinces: an introduction.
Earth Science Review, 17, 1–29.
AUSTIN, G. T. (2001) Reviving a legend. Colored Stone, 14 (1),
510–511.
BANK, H., and HENN, U. (1990) Paraíba tourmaline: beauty and
rarity. Jewellery News Asia, no. 70, 62, 64.
BANK, H., HENN, U., BANK, F. H., von PLATEN, H., and
HOFMEISTER, W. (1990) Leuchtendblaue Cu-führende Turmaline
aus Paraíba, Brasilien. Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 39 (1), 3–11.
BARBOSA, H., and COOK, B. C. (1991) Copper tourmaline from
Paraíba, Brazil. Privately printed circular, 1 p.
BRANDSTÄTTER, F., and NIEDERMAYR, G. (1993) Einschlüsse
von gediegen Kupfer in Cu-elbaite von São José da Batalha,
Paraíba, Brazilien. Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 42 (1), 37–41.
BRANDSTÄTTER, F., and NIEDERMAYR, G. (1994) Copper
The Mineralogical Record, volume 33, March–April, 2002