Paravauxite, Sigloite
Miniature, 5.0 x 3.3 x 1.3 cm
Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosi Department, Bolivia
This is a fine specimen featuring an attractive group of lustrous, water-green color Paravauxite crystals and some minor tan color Sigloite crystals on matrix. Sigloite forms as an alteration of Paravauxite. I found one very small but unique crystal of Paravauxite under the microscope which I have photographed. The crystal has two blue "stripes" running along corresponding sides of the prism face, and my assumption is that this may be a micro "wash" of another phosphate, i.e. Vauxite or Vivianite. I have never seen a crystal quite like this from Bolivia or any other locality for Paravauxite. The largest Paravauxite crystal measures 7 mm. This specimen is from the type locality for both Paravauxite and Sigloite. Mark Chance Bandy described Paravauxite crystals in his book "Mineralogy of Llallagua, Bolivia." He states that Paravauxite is the most abundant of all the "Vauxites" from this mine." This piece is a great example of the prismatic, sheaf-like parallel growths that Mr. Bandy described.