Amethyst is a violet variety of quartz often used in jewelry. Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue.
| Color | Purple, violet |
| Mohs scale hardness | 7–lower in impure varieties |
| Specific gravity | 2.65 |
| Refractive index | 1.543 – 1.553 |