0.70 ct BRAZILIANITE – BRAZIL

Brazilianite represents the "neon-citrus" peak of the phosphate world. A sodium aluminum phosphate, it is a species I have always respected for its unique, "chartreuse" yellow-green color—a hue that is so distinct it has become synonymous with the mineral itself. First discovered in 1944, it was initially mistaken for Chrysoberyl due to its color and hardness, but for the specialist, Brazilianite is a prize of late-stage hydrothermal perfection. It typically presents as sharp, monoclinic prisms with a vitreous to pearly luster. It is a stone of "crystalline energy," providing a sophisticated, "open" brilliance that makes it a true centerpiece for any elite systematic vault.

Historical Significance: Brazilianite is one of the most famous "new" minerals of the 20th century. Historically, its discovery caused a sensation in the gemological world because it was the first high-quality, gem-grade phosphate that could be faceted into large, durable stones. In the world of fine minerals, it is celebrated for its complex, "spear-like" morphology and its remarkable transparency. It stands as a symbol of mid-century mineralogical discovery, bridging the gap between common pegmatite phosphates and the elite world of "investment-grade" precious rarities. It serves as a reminder that even in well-explored mining regions, nature can still yield "neon" surprises that challenge our established classifications.

Discovery: The mineral was formally named in 1945 by Frederick Pough and Edward Henderson in honor of its country of origin, Brazil. Scientifically, it is a sodium aluminum phosphate. Its discovery in the Córrego Frio Mine provided mineralogists with the first clear look at this specific chemical arrangement, which only occurs under very precise pressure and temperature conditions within evolved granite pegmatites. My own respect for this material grew from observing its pleochroism; in the best specimens, the shift between "lemon-yellow" and "mint-green" is subtle yet captivating, adding a liquid depth to the stone.

Important Mines: The undisputed world capital for the finest Brazilianite crystals is the Córrego Frio Mine in Linópolis, Minas Gerais, Brazil. This type-locality has produced the legendary "spear" crystals that set the global benchmark. I also have a high regard for the spectacular, "gemmy" clusters found in the Telírio Mine, also in Minas Gerais, and the rare, smaller occurrences in New Hampshire, USA. For the vault, I prioritize the Linópolis material for its unmatched "neon-yellow" saturation and its textbook crystal definition.

Description: Brazilianite is a sodium aluminum phosphate that crystallizes in the monoclinic system. It sits at a 5.5 on the Mohs scale, making it a relatively durable mineral for a phosphate, though it is quite "brittle" and possesses a perfect cleavage that requires a master's touch when cutting. It is characterized by its vitreous luster and its unmistakable "citrus" color palette.

One of its most identifying traits is its perfect basal cleavage ({010}) and its specific gravity ($SG \approx 2.98$), which makes it feel slightly heavier than Quartz. It has a moderate refractive index ($n \approx 1.60$ to $1.62$) and a characteristic "fibrous" or "striated" texture on certain crystal faces. Because it is a pegmatite mineral, it is often found in association with Muscovite, Albite, and Apatite. When I select a piece for the collection, I look for "razor-sharp" prismatic terminations and a "liquid-clear" interior, as these highlight the sophisticated, three-dimensional geometry that makes Brazilianite a standout for the systematic specialist. It is a light, high-vibration mineral that offers a unique, "electric" beauty unlike any other phosphate species.

Chemical Formula: NaAl₃(PO₄)₂(OH)₄