The Mines and Gemstones of Minas Gerais, Brazil

Denise Nelson

Denise Nelson

Denise Nelson of Inner Circle gave us a virtual tour of some of the mining areas of Minas Gerais, Brazil during our June 21st meeting. She began visiting the mines four years ago and has become an engaging speaker on the topic accompanied by photos showing the different areas and techniques.

Aquamarine, Rosequartz, Bicolored Amethyst

Aquamarine, Rosequartz, Bicolored Amethyst

Belo Horizonte is the current, gem-industry driven capitol of the province of Minas Gerais, and is also the home to numerous private gem collections. The cities of Gov. Valadares and Teofilo Otoni are centers of active gem trading, cutting and marketing..

 Rough Imperial Topaz crystals from  the  Ouro Preto region

Rough Imperial Topaz crystals from the Ouro Preto region

The Itabira region is known for being iron-rich, as well as a producer of emeralds. The key to locating emeralds here is the contrasting white calcite and black biotitic and chloride shist. This indicates the presence of emeralds. The mining in this area consists of shaft and tunnel-mining.

Natural color blue Topaz necklace, Watermelon Tourmaline and  Garnet cabochons from Minas Gerais

Natural color blue Topaz necklace, Watermelon Tourmaline and Garnet cabochons from Minas Gerais

We got a look at historic Ouro Preto which means “black gold” (not Texas tea) and was once the capital of Minas Gerais. We saw many gold-decorated buildings in the colonial style and there is a historic Mineralogy Museums as well as a world-famous School of Mining. Imperial Topaz was discovered in the surrounding area in 1735, just a few years after the big diamond discovery near the town of Diamantina. This alluvial diamond deposit provided most of the world’s gem-diamonds for 150 years, before the South African discoveries.

Rough Tourmaline crystals in Quartz, collected in Minas Gerais

Rough Tourmaline crystals in Quartz, collected in Minas Gerais

The Navigator mine rights are privately owned and one of the richest producers of a variety of minerals and gem-stones Brazil is famous for. It is a cave mine and dynamite is used in the process.

Some of the mines are quite primitive, literal holes in the ground while others have some of the latest equipment and technology available.

Citrines after heat-treatment

Citrines after heat-treatment

South of Minas Gerais, in Rio Grande del Sul tunnel mining leads to large amounts of quartz geodes. Here, the geodes range from the small to the enormous.. Some of the geodes are heated prior to being offered for sale to turn the sublime into fantastic citrine, and darken the color of purple amethyst. Another region produces opal, which is harder and tends to craze less than some of the Australian counterparts.

A brazilian crystal from Courtland Lee's table

A brazilian crystal from Courtland Lee's table

One last tidbit that Denise shared was that in cutting the stones that the mines yield, calibration has not always been a priority. They have always cut to retain weight. The cutters have recently discovered that they can get more for the stones if they are cut to calibration and have begun doing so. They are now producing, along with standard shapes, excellent innovative and unique cuts complimenting bi-colored Tourmaline and Quartz.

A table of members having a pre meeting discussion

A table of members having a pre meeting discussion

The jewelry that is designed by Brazilians is very contemporary and bold. They are not averse to using cabochons and highly included gems as well. Many of their designs incorporate natural crystals. One of the more impressive pieces shown was a suite made of purplish-red imperial topaz crystals and gold.

Ira Kramer, Dennis Nelson, and Denise Nelson

Ira Kramer, Dennis Nelson, and Denise Nelson

In closing, Denise had several stones and crystals that she has collected during her last three trips and we were given the opportunity to examine up close some of the wonders of Brazil!

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