Medina pegmatite field

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Pedra Azul pegmatite district, Minas Gerais, Brazil

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Key Information

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  • The Medina pegmatite field is located in the Pedra Azul pegmatite district, northeast Minas Gerais, Brazil, known for gemstone production.

  • It produces high-quality aquamarine, topaz, and the rare mineral herderite, with other minerals like fluorapatite and muscovite.

  • The geological structure consists of granite-associated pegmatites, biotite-rich and tourmaline-poor, forming through crystallization.

  • Mining likely started decades ago, possibly by local miners, with ongoing small-scale operations.

  • The area has a tropical climate, with wet and dry seasons, and a rich cultural heritage tied to agriculture and gemstones.

  • An unexpected detail is the lack of specific protected ecological areas, despite the region’s mineral wealth.

Location and Minerals

The Medina pegmatite field lies in the northeast of Minas Gerais, Brazil, within the Jequitinhonha River valley, encompassing the cities of Pedra Azul and Medina. This area is famous for its pegmatite fields, which yield gemstones like aquamarine and topaz, alongside the rare herderite, adding unique value for enthusiasts.

Geological and Mining Context

Research suggests the pegmatites are linked to granite, with a biotite-rich, tourmaline-poor composition, forming through slow crystallization. Mining history indicates small-scale operations, likely starting decades ago, continuing today, driven by local collectors and miners.

Cultural and Environmental Notes

The region enjoys a tropical climate, with temperatures ranging from 59°F to 90°F, featuring distinct wet and dry seasons. Culturally, Pedra Azul is rooted in traditional Brazilian life, with an economy influenced by agriculture and gemstone trade, though specific festivals are not well-documented.

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