Amethyst Beads and Strands - Don't Let Them String You Up
The difference between good and not so good gemstone beads are the same criteria as with traditional gemstone shapes...the cut and the qualities of the color.
The cut is something to be careful of, really careful. Take a look at the drill hole, how smooth is it? If it's ragged it's going to chew up your silk and you'll be restringing your strand frequently. That, or have it strung on wire. If the beads are pear shape, how well do the shapes match, are the tips in one piece or broken off? How uniform are the beads? Hold them up to the light...do they sparkle? Hold them down without much light, can you still see that they're definitely purple?
Color. First, the intensity of the color depends upon you...would you like them like or dark or somewhere in between? As far as quality (and value), what's true for amethyst is true for all gems: the darker the color MAINTAINING CLARITY AND BRILLIANCE the better. It's no use if the beads are dark and you can't see that they're purple. How about inclusions...unless it's a less expensive strand, amethyst shouldn't have much if any inclusions. Hold them up to the light...how uniform is the color and clarity?
Last...ask if the beads have been treated. If they have, there's a good chance the color will fade over time.