Córrego Frio mine, Linópolis, Divino das Laranjeiras, Minas Gerais, Brazili

Regional Level Types
Córrego Frio mine	Mine (Inactive)
Linópolis	Town
Divino das Laranjeiras	Municipality
Minas Gerais	State
Brazil	Country

A granite pegmatite 6 kilometres northwest of the village of Linópolis, east of Governador Valadares. Located close to the border of Divino das Laranjeiras and Mendes Pimentel municipalities. Various names have been applied to this locality.

Aimorés pegmatite district, Eastern Brazilian pegmatite province.

Type locality for Brazilianite, see Cassedanne (1983) and also discussion at https://www.mindat.org/mesg-199894.html

Mine Information: Originally developed as an open-pit mine a year after discovering a gemmy mineral in 1942, which was later (in 1945) determined to be brazilianite. The cleavability and softness were thought to be the result of weathering, so 2 short exploratory adits were driven.

In late 1944, E.R. Swoboda, an American mineral dealer, aware of the rarity of the crystals, obtained a lease on the locality and supervised the additional excavation of the pegmatite, providing the United States Geological Survey with a number of fine specimens for their use.

Geology: Eastern Minas Gerais is for the most part underlain by Precambrian dark-coloured schists and gneisses, light-coloured granitoid gneisses, and sericitic quartzites. Locally, the pegmatite strikes approximately east-west, dips steeply to the north, and is a tabular mass essentially in alignment with the schistosity of the hosting biotite-garnet schist. Its thickness ranges from 3 meters at the surface to 1.5 meters in the lower crosscut adit.

Texturally and compositionally, the pegmatite can be subdivided into three units working in a massive border zone (massive albite with minor quartz and muscovite), a crystal cavity zone, and a quartz lens.
The border zone contains thin, elongate, blue-green masses of scorzalite and souzalite, up to 25 cm long, extending across the zone normal to the contact.
The cavity zone is characterized by irregular vugs and crystal cavities bordered by stubby, terminated quartz crystals, well-formed brazilianite crystals, and rhomboid masses of limonite-stained muscovite. Cleavelandite and porous and massive albite all occur in this zone, and in general, a higher proportion of quartz and muscovite occur here.
The quartz zone was mined out by 1947.

Albite, muscovite, and quartz make up more than 99 percent of the pegmatite. Six phosphate minerals are present including scorzalite and souzalite, brazilianite, blue-green apatite, and two unidentified [as of 1947] phosphates. Tapiolite and zircon are rare accessory minerals. Beryl and tourmaline, found in the stream bed below the pegmatite, were not observed in the exposed parts of the pegmatite.

As is true for many of the regional pegmatites, a well-defined contact with schist and the texture of the border facies support the hypothesis of intrusion of a magmatic fluid which consolidated from border to centre after emplacement.

Massive albite is characteristic of the early stage of pegmatite consolidation, whereas cleavelandite has formed in the late stage. Scorzalite, souzalite, and apatite are intermixed with massive albite in the border zone and are included by crystals of brazilianite and quartz in the crystal cavity zone. Shell-like intergrowths of apatite and massive albite in the outer margin of the crystal cavity zone indicate that apatite began to form near the end of massive albite formation.
The field relations support the hypothesis of continuous crystallization from a magmatic to an autohydrothermal stage.

Other Regions, Features and Areas containing this locality

References