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Alexandrite

Tsarstone collectors guide

Brazilian alexandrite

Alexandrite is rare and usually low quality, although in the past few years some very excellent specimens of alexandrite from the Carnaiba mine appeared on the market. One pegmatite near Jaqueto yielded a 120,000 carat twinned crystal.

Locality details
CountryBrazil
RegionNortheast Region
ProvinceBahia
LocalityCarnaiba mine
Latitude-10.7333
Longitude-40.3500
Altitude1502
Time zoneUTC -3 (-2DT)
Locality maps
MapSatellite
Map of Carnaiba Satellite of Carnaiba

In the region surrounding the Carnaiba deposit, Middle Proterozoic quartzites, phyllites, and quartz-chlorite schists are intruded by granite. Within this succession are tabular serpentinites and serpentine-talc schists covering an area of 10 to 15 km by 200 m that are surrounded by granite. Emerald occurs in the serpentinites adjacent to granite and also within a large xenolith in granite. Oligioclase-beryl-muscovite pegmatite and quartz veins with beryl, apatite, tourmaline and sulfides also are found within the ultramafics and less often within quartzite.

Biotite-phlogopite-schist and phlogopite-talc-schist which contain emerald and alexandrite lie near veins in tectonic zones within the ultramafics. The emeralds have Cr2O3 contents up to 0.73% and are disseminated in glimmerites and generally are 2 to 3 cm (0.8 to 1.2 in) in length. Some of the emeralds are high quality but mixed with considerable amounts of low-quality material.


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Bibliographic details
Page title Brazilian alexandrite, Carnaiba Mine
Author David Weinberg
Website title Alexandrite Tsarstone Collectors Guide
Date published 03 July 2010 06:11 UTC
Date accessed 16 April 2014 18:16 UTC
Permanent link http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003
AMA style
David Weinberg. "Brazilian alexandrite, Carnaiba Mine". In Alexandrite Tsarstone Collectors Guide. July 03, 2010, 06:11 UTC. Available at: http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003. Accessed April 16, 2014.
APA style
"Brazilian alexandrite, Carnaiba Mine". (2010, July 03). In Alexandrite Tsarstone Collectors Guide. Retrieved 18:16, April 16, 2014, from http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003.
Bluebook style
"Brazilian alexandrite, Carnaiba Mine", http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003 (last visited April 16, 2014).
Bluebook: Harvard JOLT style
See Alexandrite Tsarstone Collectors Guide, "Brazilian alexandrite, Carnaiba Mine", http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003 (Information about Brazilian alexandrite findings and mining in Pindobacu, Brazil) (as of Apr. 16, 2014, 18:16 GMT).
CBE/CSE style
David Weinberg. "Brazilian alexandrite, Carnaiba Mine". In Alexandrite Tsarstone Collectors Guide. 2010 Jul 03, 06:11 UTC.[Internet], Alexandrite Tsarstone Collectors Guide; 2010 Jul 03, 06:11 UTC [cited 2014 Apr 16]. Available from: http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003.
Chicago style
David Weinberg, "Brazilian alexandrite, Carnaiba Mine", http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003, (accessed April 16, 2014).
MLA style
"Brazilian alexandrite, Carnaiba Mine". Alexandrite Tsarstone Collectors Guide. 03 Jul 2010, 06:11 UTC. 16 Apr 2014 http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003
MHRA style
David Weinberg, "Brazilian alexandrite, Carnaiba Mine", Alexandrite Tsarstone Collectors Guide, 03 July 2010, 06:11 UTC, http://www.alexandrite.net/viewpage.html?id=ALXS-001-00003 [accessed 16 April 2014].
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