Boulder opal from Australia 9.70 ct

A colorful specimen of natural stone boulder opal in the form of a free cabochon (free form boulder opal). The pattern of opal veins in the rock resembles an old sailing map, on which the outlines of rivers and oceans are drawn. The stone's play is incredible! The cabochon contains blue, light blue, red, yellow, violet colors, it looks different from different angles of view.