Most imperial topaz crystals exhibit a core color of orange, for which this important gem and mineral mining district is well known. Rarely, perhaps once each decade, one sees a startlingly rich purple color in crystals like this one. Glassy and gemmy, and well formed, this crystal is truly a pure purple color with no orange. This is the rarest of the rare, for gem crystals from Brazil. The piece is a large (competition-worthy) thumbnail and among the largest I have seen of purple topaz from the mine. 52 carats in mass - very large for this varietal topaz species.