Gorceixite - Encyclopedia
Class : Phosphates, arsenates, vanadates
Subclass : Hydrated phosphates
Crystal system : Monoclinic
Chemistry : BaAl3(PO4)(PO3OH)(OH)6
Rarity : Quite common
Gorceixite is a barium aluminum phosphate. It is mainly found in granitic pegmatites, lateritic phosphates and many sedimentary rocks. It is also well known in pneumatolytic tin and tungsten deposits, in carbonatites, hydrothermalized dolomites and hydrothermal alteration zones ; it is an accessory component of certain soils, which is also concentrated in alluvium : the "favas" of diamondiferous sands are small gorceixite gravels. It was named in honor of Henrique Gorceix, director of the Ouro Preto School of Mines in Brazil. Gorceixite is a colorless mineral, or often tinged with a more or less deep brown, sometimes pale green or blue. Crystals are rare, and gorceixite generally presents as small 1 cm spheroidal concretions with a fibroradiated texture.
Main photo : Gorceixite from Échassières, Allier, France © Pascal Chollet
Gorceixite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 6
Density : 3.03 to 3.18
Fracture : Conchoidal
Streak : White
TP : Translucent to transparent
RI : 1.610 to 1.625
Birefringence : 0.010
Optical character : Uniaxial +
Pleochroism : None
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : None