Brachyuchamine

Brachyuchamine is a rare and distinctive mineral species, first discovered in 2005 in the Brachyuca mine, located in the state of Minas Gerais, Brazil. It is a member of the uranyl phosphate group of minerals, characterized by its unique chemical composition and crystal structure. The mineral is named after the Brachyuca mine, where it was found, and the Greek word "uchamine," which refers to the mineral's uranyl phosphate composition.

Brachyuchamine crystallizes in the monoclinic system, forming prismatic crystals that can reach up to 1 cm in length. It typically occurs as yellow to orange prismatic crystals, although color variations can occur due to impurities. The mineral has a Mohs hardness of approximately 2.5 and a specific gravity of around 4.2 g/cm³. Brachyuchamine is soluble in hydrochloric acid and exhibits a strong fluorescence under ultraviolet light.

The mineral's chemical formula is (UO2)2(PO4)2·4H2O, indicating that it is a hydrated uranyl phosphate. The uranyl ion (UO2)²⁺ is a common constituent in many uranium minerals, while the phosphate ion (PO4)³⁻ is found in various phosphate minerals. The presence of water molecules in the crystal structure contributes to the mineral's hydration.

Brachyuchamine is of interest to mineralogists and collectors due to its rarity and distinctive properties. Its occurrence is limited to the Brachyuca mine, making it a valuable specimen for those studying the mineralogy of the region. Despite its rarity, brachyuchamine remains an important addition to the mineralogical community's understanding of uranyl phosphate minerals.