Agate, Polyhedroid (Mineral)

These unusual, but stunning agates formed in geometric pattern shapes rather than the more common round or oval agate shape. Geologists still have not come to an agreement on how these formations came about. The most agreed upon formation theory seems to be that the sharp geometric shapes are thought to have been formed in the voids between interlaced crystals of Barite, or possibly Calcite crystal formations. The agate nodules can be solid or hollow and most have distinct, colourful fortification agate bands that follow the typically triangular or trapezoidal shape of the Polyhedroid Agate.