In my opinion this is a true color changer. I have run into a few on the inter net, but this is the only one in the collection. I did not realize that I had a another type of color changer when I bought the rough. I can tell that it is a dravite from the absorption graphs produced by my spectrometer, which look a lot like chrome tourmaline. But of course chrome tourmaline, which is probably not colored with chrome, is always green and does not change color. Which chromophores chrome, vanadium or more I do not know or their concentrations and I wish that I could find something out about it. The gemstone appears to be eye clean, not dichroic and with good crystal. It weighs 2.92 carats. and has a medium dark tone level.