Amethyst is the most valuable stone in the quartz group. The color can range from a light purple to a very dark rich purple. It is known as a color for royalty. It is said to have many supernatural powers; it brings luck, ensures constancy, protects against magic and home sickness. Amethyst is 7 on the Mohs hardness scale, and care should be taken when wearing. It is the birthstone for February and astrological sign Pisces.