Re-polishing the Crown of a Tanzanite.
A jeweler contacted us regarding a large Tanzanite mounted in a heavy ring. The Tanzanite showed heavy wear and needed re-polishing.
When they emailed me a photo of the piece, the color looked like a synthetic Sapphire because it was such a pure blue with none of the usual violet secondary color.
When I received the ring, I tested it on my refractometer and, sure enough, it was a Tanzanite.