Polyhedral agate - Paraiba, Brazil

Polished slice of polyhedral agate. Polyhedral agates were discovered in the 1970s in the state of Paraíba, Brazil. They were formed by complete or partial filling of cavities of polyhedral shapes, often triangular, interpreted either as corresponding to a type of dissolved crystal often assumed to be calcite (pseudomorphosis), or as being the interstices between old undetermined crystals.

5,4 x 0,8 x 0,3 cm.