Córrego Frio is the locality that gave brazilianite its name, its scientific standing, and much of its collector mystique. The best crystals from this mine have the unmistakable look that made the species famous: transparent to translucent yellow-green prisms with a glassy luster, complex monoclinic terminations, and a color range that collectors often describe as chartreuse, olive-yellow, or greenish gold. Fine examples can be small but intensely gemmy; larger ones are coveted because brazilianite combines a relatively low hardness, good cleavage, and a strong tendency toward internal cracking, so pristine display crystals are much scarcer than the early production numbers alone would suggest.
Photo: Wikimedia Commons
The mine is a small but extraordinarily important phosphate-bearing granitic pegmatite near Linópolis, in the Divino das Laranjeiras area of eastern Minas Gerais. Mineralogically it is far more significant than its modest dimensions imply: brazilianite, scorzalite, and souzalite all have their type-locality roots here. The pegmatite is an albite–muscovite–quartz body with phosphate mineralization concentrated between a quartz core and albite-rich border zones, set in biotite-garnet schist of the São Tomé Formation within the Eastern Brazilian Pegmatite Province.
For collectors, Córrego Frio brazilianite is the benchmark against which other localities are compared. Newer Minas Gerais pegmatites, especially the nearby Telírio workings, have produced attractive material, but the old Córrego Frio crystals retain a special authority: they are the type-locality material, many came from the early 1940s production, and the best pieces show the classic combination of sharp form, saturated greenish-yellow color, gem transparency, and historical provenance.
Photo: Mineral Auctions
Córrego Frio Mine is recorded near Linópolis, Divino das Laranjeiras, Minas Gerais, at approximately 18° 40' 9" S, 41° 28' 13" W. The mine has also appeared in older literature and labels under variants such as Corrego Frio, Lavra da Brasilianita, Lavra do Duquinha, and names tied to the older Conselheiro Pena regional geography. Serious collectors should expect label variation, especially on older specimens that entered the United States market in the 1940s and 1950s.
The deposit is a narrow, tabular granitic pegmatite of the Aimorés pegmatite district, within the Eastern Brazilian Pegmatite Province. It strikes roughly east-west, dips steeply north, and lies broadly parallel to the foliation of the enclosing biotite-garnet schist. Classic descriptions divide the pegmatite into a massive albite-rich border zone, a crystal-cavity zone, and a quartz lens. The border zone is dominated by albite with subordinate quartz and muscovite; the crystal-cavity zone contains the best-developed brazilianite, quartz, cleavelandite, porous albite, and limonite-stained muscovite.
The mine was developed after yellow-green transparent crystals were discovered in the early 1940s and initially confused with better-known gem minerals. By late 1944, the American mineral dealer E. R. Swoboda had obtained a lease and supervised additional excavation. In 1945 and 1946, Córrego Frio brazilianite was offered to museums, dealers, and private collectors in the United States, placing the species quickly into the top tier of postwar collector minerals.
Córrego Frio was never a vast mine. Geological descriptions give a pegmatite only a few meters thick, with the quartz lens largely removed by the late 1940s. The largest crystal reported in the early literature weighed about 2 kg, but that crystal was broken while people tried to obtain gem-clear pieces. A roughly 1 kg crystal was described as being on display at the U.S. National Museum, and about a dozen crystals in the 100 g to 1,000 g range were known from the early production. Most individual crystals, however, were much smaller: commonly less than an inch across and under 10 g.
Modern studies describe the old Córrego Frio working as abandoned and internally collapsed. That matters to collectors: this is not a locality where fresh pocket production can be assumed. Most good specimens on the market are older pieces, recycled collection specimens, or material from past episodic finds attributed to the mine and its immediate area. Field access should not be assumed; the locality is an old mine site in a region of private workings, changed municipal boundaries, and potentially unsafe underground conditions.
Brazilianite from Córrego Frio is NaAl3(PO4)2(OH)4, a monoclinic sodium aluminum phosphate hydroxide. The classic Córrego Frio habit is a short to elongated prism, commonly with a narrow prism zone and elongation parallel to [100]. Better crystals may be doubly terminated and carry numerous faces; George Switzer’s study of 37 crystals from the Pecora-Swoboda material found that the most complete examples showed 20 to 30 faces.
Color is one of the locality’s great signatures. Córrego Frio crystals range from pale greenish yellow through golden yellow to rich chartreuse yellow-green. The best pieces are bright without looking artificial, and they transmit a warm yellow-green glow through the body of the crystal. Modern color studies of Minas Gerais brazilianite show that the yellow component is tied to a near-ultraviolet absorption band associated with localized O1- hole centers, while the greenish component is linked to a broad red-region absorption band whose origin remains less certain. In practical collector terms, color should be judged in daylight or neutral light: overly dark, brownish, or sleepy crystals lose much of the distinctive Córrego Frio character.
Crystal size varies widely. Early American Mineralogist work documented crystals from the Pecora-Swoboda collection measuring roughly 0.5 to 4 cm across and weighing under 1 g to 32 g, while the overall early mine production included a few far larger individuals. Museum-scale crystals exist, but most obtainable specimens are thumbnails to miniatures. A transparent, sharp, damage-free crystal over 2 cm is already a serious specimen; a fine matrix piece with multiple sharp gem crystals is considerably rarer.
Matrix is important. Many Córrego Frio specimens are loose crystals or clusters with little matrix, but highly prized examples show brazilianite on albite, cleavelandite, quartz, or muscovite. Muscovite associations can be especially attractive: tan to golden-brown books or bladed aggregates provide a warm contrast to the yellow-green brazilianite. Albite and cleavelandite are the commonest pale matrix minerals and can help support a type-locality attribution when the overall habit and provenance are consistent.
Associated minerals recorded from the pegmatite include albite, cleavelandite, muscovite, quartz, microcline, fluorapatite, childrenite, eosphorite, frondelite, dufrénite, jahnsite-group minerals, roscherite, sabugalite, scorzalite, souzalite, strunzite, wyllieite, tapiolite, zircon, uraninite, arsenopyrite, garnet-group minerals, and tourmaline. The famous blue to blue-green phosphates scorzalite and souzalite are not merely associates; they are part of the type-locality importance of Córrego Frio itself.
Quality is judged by a combination of color, transparency, crystal definition, and condition. Top specimens have a saturated but natural yellow-green color, bright vitreous luster, sharp monoclinic terminations, minimal internal shattering, and no obvious bruising along edges or cleavage directions. Because brazilianite has a good cleavage and only moderate hardness, even fine crystals often show small edge rubs, contacts, internal veils, or repaired-looking cleavage surfaces. These should be evaluated realistically rather than automatically dismissed; truly pristine crystals from the type locality are exceptional.
The main authenticity issue with Córrego Frio brazilianite is not a flood of synthetic fakes but the more subtle problem of attribution, condition, and possible misidentification. Historically, the mineral itself was confused with chrysoberyl, beryl, or other yellow-green gem minerals before its recognition as a new species. In today’s market, well-formed yellow-green phosphate crystals from Minas Gerais may be labeled broadly as “Linópolis” or “Corrego Frio” even when they come from nearby pegmatites. Provenance matters: old labels, collection history, dealer reputation, and consistency of habit are all important.
True Córrego Frio examples often have a particular look: sharp yellow-green monoclinic prisms, commonly blocky to elongated, sometimes on albite or muscovite, with the classic type-locality color. Nearby Minas Gerais material can be excellent but should not be silently upgraded to Córrego Frio without evidence. Serious buyers should ask whether the specimen is specifically from Córrego Frio Mine, from the broader Linópolis area, or from another named pegmatite such as Telírio.
Treatment is a nuanced subject. Laboratory work on Minas Gerais brazilianite shows that gamma irradiation can intensify the yellow component of the color, while heating can reduce the intense yellow component across a temperature range that varies by sample. That does not mean that most collector crystals have been treated; rather, it means color should be considered with the same caution applied to other gem minerals whose chromophore systems can be altered experimentally. Suspiciously uniform, unusually intense yellow color in loose gem rough deserves scrutiny, especially if the specimen lacks matrix and provenance.
Condition is central. Brazilianite’s Mohs hardness is about 5.5, and the species has good cleavage. Chips on terminations, bruised prism edges, cleaved backs, contacts from pocket growth, and internal fractures are common. Matrix specimens can be fragile because brazilianite crystals may sit on friable albite or mica. Repairs are possible, particularly on expensive matrix pieces, so inspect junctions under magnification for glue, mismatched luster, unnatural gaps, or crystals that seem too neatly placed.
Rarity is best understood by quality tier. Small imperfect crystals and old reference pieces appear regularly enough that the species is obtainable. Fine Córrego Frio crystals with gem transparency, sharp complete terminations, and unquestioned type-locality provenance are scarce. Matrix specimens are scarcer still, especially when the brazilianite crystals are gemmy rather than cloudy. Large, historic, damage-free crystals belong in the museum-and-major-collection category.
Market availability is intermittent. Auction records and dealer listings show that type-locality specimens still circulate, from modest miniatures to high-end matrix pieces. Older examples from named collections command premiums because they carry what the locality itself now lacks: documentary continuity back to the classic finds. For serious collectors, a Córrego Frio brazilianite should be bought as a historic mineral specimen first and a pretty yellow-green crystal second.
The discovery story begins with a mistake that any gem hunter can understand. In 1942, at Córrego Frio, a farmer found several kilograms of a greenish mineral that looked valuable enough to be taken for beryl or chrysoberyl. The color was persuasive: yellow-green, glassy, and gemlike. But the illusion did not survive careful handling. Lapidaries soon realized the material was softer than expected and not ideal for jewelry use, and the mineral’s crystal habit did not match chrysoberyl.
Frederick H. Pough encountered the material while in Brazil during World War II, when he was working on strategic mineral questions rather than hunting for a new gemstone. The mission involved quartz and elbaite for wartime technical uses, but Pough had the eye of a mineralogist and noticed that the supposed chrysoberyl was wrong in exactly the interesting way: similar enough in color to fool the trade, but different in habit and hardness. He obtained crystals and sent them to Edward P. Henderson at the Smithsonian Institution. Henderson’s analysis showed that the yellow-green “chrysoberyl” was not chrysoberyl at all. It was a new sodium aluminum phosphate, formally described in 1945 and named brazilianite for its country of origin.
The little mine then moved quickly from local curiosity to international mineral fame. E. R. Swoboda obtained a lease in late 1944 and oversaw further excavation. In 1945 and 1946, crystals from Córrego Frio were being offered to American museums, dealers, and collectors. The timing is part of the romance of the locality: a small pegmatite in eastern Minas Gerais, a wartime mineralogist, a dealer alert enough to recognize rarity, and a new gemstone species entering collections almost as soon as it entered the literature.
The early production numbers are tantalizing. About 30 kg of gem crystals and about 200 kg of lower-grade specimen “pound material” were reported from 1943 to 1946. Yet fine specimens remained scarce because the gem instinct worked against preservation. Many transparent crystals were destroyed before or during lapidary work, and the most dramatic casualty was a many-faced crystal said by miners to have weighed about 2 kg. It was broken up in an attempt to obtain gem-clear pieces. The loss still stings: in specimen terms, that single crystal might have been one of the great phosphate minerals of the world.
Not all giants disappeared. A crystal of about 1 kg was recorded as displayed in the U.S. National Museum in Washington, D.C., and around a dozen other crystals in the 100 g to 1,000 g range were known. These numbers put ordinary market specimens in perspective. A 2 cm clean crystal is not “small” in the meaningful collector sense; it belongs to a species and locality where the majority of surviving crystals are modest and where the truly large stones were either cut, broken, or locked into institutional collections long ago.
The mine’s scientific afterlife was just as important as its specimen production. Córrego Frio produced not only brazilianite but also scorzalite and souzalite, two additional phosphate species described shortly afterward. The pegmatite became a compact lesson in phosphate mineralogy: albite, muscovite, and quartz making up nearly all of the rock, while rare phosphates carried the locality into the mineralogical record. Later field descriptions of the old working are sobering. The classic mine is now abandoned and internally collapsed, a quiet end for a place whose crystals once moved from a Minas Gerais hillside into the drawers of the Smithsonian and the cabinets of the world’s best collectors.
Pough, Frederick H., and Henderson, Edward P. “Brazilianite, a New Phosphate Mineral.” American Mineralogist 30, 572–582, 1945. The original formal description of brazilianite; Mindat’s brazilianite page records the citation and identifies Córrego Frio as the type locality.
“A New Gem Stone.” Nature 157, 72, 1946. A contemporary note announcing brazilianite as a new gem mineral described by Pough and Henderson, with the early comparison to chrysoberyl and benitoite.
Pecora, William T., and Fahey, Joseph J. “The Corrego Frio Pegmatite, Minas Gerais: Scorzalite and Souzalite, Two New Phosphate Minerals.” American Mineralogist 34, 83–93, 1949. The key geological and mineralogical description of the pegmatite, including production figures, zoning, associated minerals, and the description of scorzalite and souzalite.
Cassedanne, Jacques P. “Famous Mineral Localities: The Córrego Frio Mine and Vicinity, Minas Gerais, Brazil.” The Mineralogical Record 14, 227–237, 1983. The classic collector-locality article cited for the mine’s species list, history, and collecting significance.
Silveira, Luiz Antônio Gomes; Chaves, Mário Luiz de Sá Carneiro; Krambrock, Klaus; Menezes Filho, Luiz Alberto Dias; Brandão, Paulo Roberto Gomes; Scholz, Ricardo; and Costa, Michele Aparecida Flores. “Ocorrência, contexto mineralógico e química mineral da brazilianita e seus depósitos em Minas Gerais.” Geociências 33(3), 378–392, 2014. Modern geological, chemical, and color-center study of brazilianite deposits in Minas Gerais, including Córrego Frio.
Scholz Cipriano, Ricardo Augusto. “Estudo dos fosfatos do distrito pegmatítico de Conselheiro Pena, Minas Gerais.” Universidade Federal de Minas Gerais doctoral thesis, 2006. A broader academic study of phosphate mineralogy in the Conselheiro Pena pegmatite district.
Cóbic, A.; Zebec, V.; Scholz, R.; Bermanec, V.; and de Brito Barreto, S. “Crystal morphology and XRD peculiarities of brazilianite from different localities.” Natura Croatica 20(1), 1–18, 2011. Comparative morphology and X-ray work on brazilianite from multiple localities, cited in Mindat’s brazilianite bibliography.
Smithsonian / National Museum of Natural History reference noted by SGB-CPRM GeoSIT: brazilianite specimen 105048. GeoSIT records brazilianite specimens from Córrego Frio in the Museu das Minas e do Metal in Belo Horizonte and in the National Museum of Natural History, Washington, D.C.
Mines Paris – PSL Mineralogy Museum visitor guide, 2019. Notes Córrego Frio brazilianite specimens in the museum, including specimen no. 6124 and an exceptional 16 cm piece, no. 8814.
Mindat locality page: Córrego Frio mine, Linópolis, Divino das Laranjeiras, Minas Gerais, Brazil — The best single online locality reference for coordinates, status, species list, geological summary, and bibliography.
Mindat species page: Brazilianite — Useful for the official formula, physical properties, type-locality status, and publication history.
SGB-CPRM GeoSIT: Pegmatito Córrego Frio — Brazilian geological heritage entry emphasizing the discovery of brazilianite, scorzalite, and souzalite at Córrego Frio.
American Mineralogist: Pecora & Fahey, 1949 PDF — Essential primary source for the mine geology, early production figures, and phosphate assemblage.
Geociências 2014 PDF: Silveira et al., “Ocorrência, contexto mineralógico e química mineral da brazilianita...” — Modern technical study of brazilianite deposits in Minas Gerais, including color-center and pegmatite-context work.
UFMG Repository: Scholz Cipriano doctoral thesis on Conselheiro Pena phosphate pegmatites — Academic context for the broader phosphate mineralogy of the district.
Wikimedia Commons: Brazilianite from Córrego Frio Mine — Freely available image of a classic small gemmy crystal from the type locality.
International Gem Society photo: faceted brazilianite from Córrego Frio — A gemological reference image for a 12.2 ct faceted stone from the type locality.
Gemdat: Brazilianite gemstone information — Gem-focused data, including notes on color stability and heat sensitivity.
Mineral Auctions archive: Brazilianite and muscovite from Córrego Frio — Market reference for a 1990s Córrego Frio brazilianite-muscovite matrix specimen.
Mineral Auctions archive: rare matrix brazilianite from Córrego Frio, ex Frank Levy Collection — Useful example of how provenance and matrix presentation affect collector value.
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