Dims: 2.83x1.69x0.63" (7.2x4.3x1.6cm)
Wt: 2.54oz (72.0g)
Llallagua, Bustillo, Potosi, Bolivia
This specimen is a book of vivianite crystals, or possibly a single crystal that has many parallel cleavage planes (which can result when a tabular crystal of vivianite is flexed, either naturally or by hand). The vivianite, while still having a bluish-green color, has darkened to a dim translucency. Only the thinnest areas show transparency. Two edges seem natural, one face is clearly cleavage, and the other is a mixture of cleavage and splintery fracture. There is a vein of something else penetrating the specimen - it looks like pyrite, but it has weathered to a brown porous material and may indeed be something else.