There was a huge kerfuffle about a year ago on the QVC board when they introduced it. If you Google it, you'll see that there is an opinion that it's not a mined gemstone and is manmade in China from glass. Others say it's part of the Quartz family (same as Amethyst as you say).
QVC I believe went on air to say it was a natural gemstone but that it had been heated or treated (can't remember which now). Gems have said on air tonight that it's mined.
I got a piece from QVC when they introduced it because I wanted to put it through it's paces. Honestly? Not my cup of tea and I certainly wouldn't pay big bucks! I'd rather have a gorgeous top class Amethyst for the colour etc. Interestingly, the Gems pieces look much more purple/pink than the QVC ones which were a blue/purple (the ones I saw anyway).
HTH
p.s. Quartz is usually cheap as chips! You pay for the faceting and goldwork typically. Having said that, a top quality Amethyst does have a value and can be worth more than you think.
