This vivianite is from the Tomokoni Adit in the Canutillos Mine in the Machacamarlin District, Cornelio Saavedra Region, Potosi Department, Bolivia. This region contains 49 different mineral species and this audit is mined exclusively for the recovery of vivianite specimens. It is a phosphate containing the elements A, X, O and H. This specimen consists of a sandstone, breccia, matrix and several crystals of vivianite. They are green with pearly sheen and a vitreous luster. When veined across the c-axis they have an emerald like translucence. This piece measures 2 x 1 1/8 x 3/4 inches or 50 x 28 x 19 mm.