Copper-Bearing Tourmalines from New Deposits in Paraíba State, Brazil

Furuya, Masashi

doi:10.5741/gems.43.3.236

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…Localiza-se 2 km a oeste de Junco do Seridó/PB. De acordo com Furuya (2007), trata-se de um pegmatito zonado, de elementos raros, completamente caulinizado, tal como Mina da Bratalha, A turmalina Paraíba ocorre na massa de caulim, associada também a mica e quartzo, com até 3,34% de CuO, em peso, nas cores azul, verde azulado e violeta. A turmalina de cor violeta, quando submetida a tratamento térmico, adquire cor azul, aumentando sua valorização no merca-do.…”

Section: Gloriousunclassified

Variedades Gemológicas De Minerais Da Província Pegmatítica Da Borborema, Ne Do Brasil: Uma Síntese

Soares¹,

Beurlen²,

Silva³

et al. 2018

Est. Geol.

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Pegmatitos graníticos são fonte de numerosos minerais com elevado potencial gerador de variedades de boa qualidade gemológica, com destaque para berilo, várias espécies do super-grupo da turmalina, topázio, espodumênio, quartzo, feldspatos, além de outros minerais menos comuns {p. ex. granadas, euclásio, gahnita, tantalita-(Mn), microlitas}. Na Província Pegmatítica da Borborema (PPB), alvo deste estudo, destacam-se as turmalinas, incluindo a famosa "turmalina Paraíba, berilo, quartzo, espessartita, gahnita, euclásio, como minerais de bom potencial gemológico. A formação destas gemas na PPB, assim como na maioria das Províncias Pegmatíticas mundiais, é localizada em cavidades situadas preferencialmente na transição entre a zona intermediaria interna e o núcleo de quartzo de pegmatitos heterogêneos mais diferenciados. A descrição das principais ocorrências de gemas da PPB será objeto deste trabalho.

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Section: Gloriousunclassified

Variedades Gemológicas De Minerais Da Província Pegmatítica Da Borborema, Ne Do Brasil: Uma Síntese

Soares¹,

Beurlen²,

Silva³

et al. 2018

Est. Geol.

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“…opper-bearing gem tourmaline-recognizable by its vivid neon blue to green color-has been one of the most popular colored gemstones on the market for the nearly three decades since its debut (figures 1 and 2). It was first discovered in the state of Paraíba in northeastern Brazil in the late 1980s, and subsequently found in the neighboring state of Rio Grande do Norte (Fritsch et al, 1990;Shigley et al, 2001;Furuya, 2007). These gems became known as Paraíba tourmalines after the locality of their discovery.…”

mentioning

confidence: 99%

Geographic Origin Determination of Paraiba Tourmaline

Katsurada¹,

Sun²,

Breeding³

et al. 2019

G&G

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Vivid blue to green copper-bearing tourmalines, known as Paraíba tourmalines, are recovered from deposits in Brazil, Nigeria, and Mozambique. These tourmalines are sought after for their intense colors. Prices are based, in part, on the geographic origin of a stone, and determining provenance is thus an important aspect for Paraíba tourmaline. However, their geographic origin cannot be established by standard gemological testing and/or qualitative chemical analyses. GIA has established sophisticated criteria requiring quantitative chemical analyses to determine geographic origin for these tourmalines. These criteria were based on several hundred samples from known sources spanning the three countries. Highly accurate and precise quantitative elemental concentrations for Cu, Zn, Ga, Sr, Sn, and Pb are acquired with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). These data can then be plotted as a function of elemental concentration for accurate geographic origin determination. In Brief • Geographic origin can have a significant impact on the value of Paraíba tourmaline. • Quantitative chemical analysis with LA-ICP-MS provides a robust tool for origin determination. • The trace elements Cu, Zn, Ga, Sr, Sn, and Pb are the most useful discriminators for Paraíba tourmaline origin. • In limited cases where there are no matching reference data, an "inconclusive" origin determination would be required.

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Copper-Bearing Tourmalines from New Deposits in Paraíba State, Brazil

Cited by 2 publications

References 2 publications

Variedades Gemológicas De Minerais Da Província Pegmatítica Da Borborema, Ne Do Brasil: Uma Síntese

Variedades Gemológicas De Minerais Da Província Pegmatítica Da Borborema, Ne Do Brasil: Uma Síntese

Geographic Origin Determination of Paraiba Tourmaline

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