Almeidaite Locality: Unnamed deposit, Novo Horizonte, Bahia, Brazil Dimensions: 17 mm x 12 mm x 4 mm Part of fully developed cristal of Almeidaite exhibiting the typical crackled surface patterns and metallic shine. Acquired from Luiz Alberto Dias Menezes Filho with autographed label. Specimen from the type locality in Brazil. — Photo: Samuel Wanderley · CC BY 3.0
Almeidaite
Almeidaite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula PbZn₂(Mn,Y)(Ti,Fe³⁺)₁₈O₃₆(OH,O)₂.
It crystallizes in the hexagonal crystal system (space group R-3). It is a member of the Crichtonite structural group.
Key properties: Mohs hardness 6; specific gravity 4.68; Brown streak; Submetallic luster; optically uniaxial.
IMA symbol Amd, IMA status: approved, named in 2013.
Found in altered dacite 2 meters from a hydrothermal quartz vein.
It is found associated with Rutile, anatase, hematite, quartz, kaolinite, muscovite, xenotime-(Y), bastnaesite-(La).
The mineral was named to honor Professor Fernando Flávio Marques de Almeida (1916-2013) for his work on the geology of Brazil and South America.