This fantastic, hand-sized specimen of tabular, jet-black, striated Ferberite crystals with iridescent highlights is from the tungsten-tin mines of Panasqueira, Portugal. At the core of this compelling piece are several large Ferberite crystals in parallel growth that measure to 9.0 cm in length. What makes these crystals special is the rainbow iridescent tarnish along their length that ranges in color from purple to blue to yellow! Several bright Ferberite crystals criss-cross and diverge off the main cluster in the front of the piece and there are numerous brilliant crystals on the back of the piece too! A striking and commanding Ferberite piece! Panasqueira has produced some of the most impressive and attractive Ferberite specimens extant. ex Art Soregaroli collection, which contained a fabulous Panasqueira suite.