different colors as they are rotated, then they are said to be dichroic (two colors). Biaxial crystals may show three different colors, and then are said to be pleochroic (many colors). Vauxite is strongly pleochroic, colorless along X and Z and blue along Y. Environment Vauxite is a secondary mineral derived from the alteration of apatite in hydrothermal tin veins. It is found associated with wavellite Al3(PO4)2(OH)3·5H2O, metavauxite and paravauxite at the type locality, Siglo Veinte Mine (Siglo XX Mine), Llallagua, Rafael Bustillo Province, Potosí Department, Bolivia, which is the only known occurrence of this mineral. The type material is conserved at the US National Museum of Natural History, Washington DC: #97561, #103542. References External links Llallagua: http://www.highbeam.com/doc/1G1-145163326.html George Vaux: http://mineralogicalrecord.com/labels.asp?colid=318&page=1 JMol: http://rruff.geo.arizona.edu/AMS/viewJmol.php?id=00175 Iron(II) minerals Aluminium minerals Phosphate minerals Triclinic minerals Minerals in space group 2