Amethyst Flat Irregular Rectangle Bead Strand | 43x18 to 35x18x3mm | 11 Beads |Purple Amethyst Flat Irregular Rectangle Strand of Beads for Jewelry Making. These irregularly shaped Amethyst to light Amethyst beads will make unique earrings, pendants and necklaces. Amethyst is a violet variety of quartz. The ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication. Amethyst is a semiprecious stone that is often used in jewelry and is the traditional birthstone for February.