Large Cat’s-Eye Emerald from Brazil

Stefanos Karampelas, Lore Kiefert, and Wenxing Xu

Figure 1. This emerald from Itabira–Nova Era in Minas Gerais weighs approximately 43 ct (approximately 25.30 × 18.10 × 13.75 mm) making it one of the largest Brazilian cat’s-eye emeralds examined by the Gübelin Gem Lab. Photo by Janine Meyer.

Gübelin Gem Laboratories (GGL) in Hong Kong and Lucerne recently had the opportunity to examine a translucent emerald, weighing approximately 43 ct, that exhibited a pronounced and well-centered chatoyancy (figure 1). The stone had a spot RI of 1.57 and a hydrostatic SG of 2.73, and it was inert under long- and short-wave UV radiation. Microscopic observation in reflected and transmitted light presented a series of dense elongated, rectangular, and square multiphase inclusions (figure 2).

Figure 2. Multiphase inclusions of different shapes and sizes, seen in reflected light (left) and brightfield illumination (right), gave rise to the cat’s-eye effect in the Brazilian emerald. Photomicrographs by Wenxing Xu (left) and Stefanos Karampelas (right). Image width 2 mm (left) and 1.2 mm (right).

The UV-Vis absorption spectra showed the characteristic Cr³⁺- as well as Fe²⁺- and Fe³⁺- related bands. In the FTIR absorption spectra, type I and type II water molecules were observed. An intense band at around 2360 cm^–1 indicated the presence of CO₂, most likely in the multiphase inclusions. Trace-element analysis of the sample with laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) showed contents consistent with schist- and pegmatite-related emeralds. It also showed lower Li, Cs, and Rb than in emeralds related to highly evolved pegmatites, such as those from Sandawana (Zimbabwe) and Kafubu (Zambia); see J.C. Zwaan et al., “Emeralds from the Fazenda Bonfim region, Rio Grande do Norte, Brazil,” Spring 2012 G&G, pp. 2–17. The stone’s composition was consistent with emeralds from Itabira–Nova Era, Minas Gerais, based on GGL’s reference collection and the published literature on the pegmatites of the area (C. Preinfalk et al., “The pegmatites of the Nova Era–Itabira–Ferros pegmatite district and the emerald mineralisation of Capoeirana and Belmont (Minas Gerais, Brazil): geochemistry and Rb-Sr dating,” Journal of South American Sciences, Vol. 14, No. 8, 2002, pp. 867–887). This exceptional stone is one of the largest Brazilian cat’s-eye emeralds examined by GGL to date. 

About the Authors

Stefanos Karampelas is a scientific researcher, Lore Kiefert chief gemologist, and Wenxing Xu a gemologist, at the Gübelin Gem Lab in Lucerne, Switzerland.

Gem Pegmatites of Minas Gerais, Brazil: The Tourmalines of the Governador Valadares District

The previous article in this series focused on tourmaline production around the city of Araçuaí, in northeastern Minas Gerais, and discussed 20 important mines in that area. The present article turns to the major tourmaline mines in southeast Minas Gerais, in the broad area surrounding the gemstone capital, Governador Valadares. Specifically, the Cruzeiro, Golconda, Santa Rosa, and Jonas mines — all of which count among the most famous tourmaline mines in the world — are described.                                        

Brazil is currently the leader in overall production of amethyst

Brazil is currently the leader in overall production of amethyst. This article describes the author's visits to three of Brazil’s most important mining areas: Marabá, Pau d’Arco, and Rio Grande do Sul. Each represents a different geologic environment and, therefore, a variety of mining methods are used. In Marabá and Rio Grande do Sul, much of the amethyst is heat treated to become citrine.                                        

An Update on “Paraíba” Tourmaline from Brazil

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.                                        

Designer’s Love of Brazil – and its Gems – Shines in Every Piece She Creates

Karyna Sena loves the travel involved in her gem and jewelry career and has visited mines in Brazil and other countries since she was a young girl. “Tell me that you need me to go somewhere in the world,” she says, “and all I need to do is check the temperature to pack.” She is pictured at a sapphire mine near Colombo, Sri Lanka. Courtesy of Karyna Sena

The rich tapestry of Brazil − from its dances, music and Carnival festivals to its native plants, animals and fruits − finds its way into each piece of designer Karyna Sena’s jewelry.

“I try to explore the Brazilian ‘way’ in my pieces,” says Sena, a GIA GG born in Salvador, capital of the gemstone-rich state of Bahia. “Jewelry must be fun!”

Sena’s joie de vivre, and her enthusiasm for her homeland, reflects a career and life that have, in one way or another, intersected with almost the entire colored stone supply chain of Brazil.

“As the granddaughter of a miner and daughter of a gem dealer, colored gemstones run in my blood,” says Sena, whose father opened a wholesale and retail store, Lasbonfim, in 1967. Sena had a playpen in the store and grew up “crawling the floors of the family store.” She remembers finding rough colored stones mixed up with her dolls, and taking trips to mines with her family.

“I remember clearly the first time my parents took us to an emerald mine in Campo Formoso, in the countryside of Bahia,” she says. “I was the first one to jump in the hole – never afraid of the dark or high temperature. I felt like Indiana Jones looking for treasures!”

Karyna Sena as a child, left, with her mother, father and two younger brothers, at a Lasbonfim store opening and ribbon-cutting ceremony in the 1980s. “As the granddaughter of a miner and the daughter of a gem dealer, colored gemstones run in my blood,” Sena says. Courtesy of Karyna Sena

Sena was also captivated by her father’s ability to discern an emerald’s origin by analyzing its colors and inclusions. He taught her how to classify the rough and polished stones and made sure she knew the ins and outs of the family business.

“My parents gave us the best education possible and let us choose whatever we wanted to do as a career, but they made sure that we knew our business,” she says. “If we didn’t succeed in whatever career we had chosen, we would always know how to do something else.”

But Sena was “completely in love with Brazilian gemstones” and wanted the family business as her “life’s work.”

She earned bachelor’s degrees in the late 1990s in both geology and business from the Universidade Federal da Bahia and Universidade Salvador, respectively, then moved to Europe to “experience the glamour and trends of the European fashion industry firsthand, and be exposed to a diversity of styles.” She made London her home base and traveled throughout the continent (and many others) for several years.

She returned to Brazil in 2012 to design and market her own jewelry line at Lasbonfim. “Back in the ‘80s, everything available at my parents’ store was very classic,” she says. “I decided to make jewelry with ‘odd’ cuts and with gemstones that were not usually set in jewelry in 18K gold.”

Sena’s “dreams in the form of jewelry” were inspired by “the colors and the happiness of Brazil, meeting the elegance of Europe.” Her first line, Orishas, sold well – and quickly, particularly to North American tourists wanting to take home a piece of Brazil.

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She incorporated her design line, Karyna Sena, but even with her success as a designer and as the director of Lasbonfim, she felt like she was missing something – a GIA diploma. She knew about GIA because her parents often helped GIA instructors and gemologists who came to Brazil to teach or do business.
“They would trade gems for gem-testing equipment that we couldn’t find in Brazil,” she says. “I had a chance to meet some of these people and learn the importance of the work that GIA does,” she says.

“I learned a bit of theory by studying geology and lots of experience in the trade, but I wanted the international respect that a GIA gemologist has. I wanted that diploma on my wall.”
Sena moved back to London to study at the Institute’s campus there, and earned her Graduate Gemologist and AJP diplomas in 2011.

“It was a sabbatical year, entirely devoted to GIA. I always joke that I was married to GIA for that time,” she says. “You have to have passion for it. It is only with focus, commitment and passion that you can succeed. It is a hard course, but it completely pays off.”

Along with the “incredible networking opportunities,” Sena appreciates that she uses what she learned at GIA “on a daily basis” – especially as she also does valuations now.

Karyna Sena holds several leadership positions in the gem and jewelry industry, including serving as the vice president of the CIBJO retail sector. She is pictured here at a 2015 event, with (from left) Fiera di Vicenza President Facco Corrado, CIBJO President Gaetano Cavalieri and GJEPC Vice Chairman Pankaj Parekh. Photo by Paulo Alcantara /Courtesy of Karyna Sena

In addition to her many roles at Lasbonfim and Karyna Sena, she is serving as the first female president of the Bahia Association of Producers and Traders of Gems, Jewelry, and Precious Metals; is the youngest board member of the Brazilian Institute of Gems and Precious Metals; and is the vice president for the retail sector of the CIBJO World Jewelry Confederation.

“We are living in a very competitive and professional world – it is smaller and faster, and there is no room for amateurism anymore,” says Sena, who lives in Brazil with her husband, Marcelo Storel. “I truly believe that the only way to be successful and still be in the game is by being creative and professional. And you can only achieve this with education.”

About the Author

Jaime Kautsky, a contributing writer, is a GIA Diamonds Graduate and GIA AJP and was an associate editor of The Loupe magazine.