A group of quartz crystals that grade from colorless to purple, on matrix. 

The Daye Mine (also known as Fengjiashan) has been one of the most prolific of Chinese specimen producers, and has been the source of numerous calcites, as well as inesite, hubeite, and copper.  Less known were these amethysts, which came out for a short while several years ago.  This piece was in the collection of Robert Nowakowski, who for a time focused on amethyst.  It comes with his label, bearing a $400 price tag.