Is amethyst a mineral?

<C> Amethyst is pleochroic (Haidinger, 1847; Pancharatnam, 1954; Raman, 1954): when the polarization of the light is changed from parallel to the c-axis to perpendicular to the c-axis, amethyst changes its color from blue-violet to purple. read more

Amethyst is a well known mineral and gemstone. It is the purple variety of the mineral Quartz, and its most valuable and prized variety. Its name derives from the Greek "amethystos", which means "not drunken", as Amethyst in antiquity was thought to ward off drunkenness. read more

The hardness of the mineral is the same as quartz, thus it is suitable for use in jewelry. Hue and tone. 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. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East. read more