However, Artemis (goddess of virginity and the hunt) intervened and transformed Amethyst into white stone. When Dionysus saw what had happened, he repented and poured wine over the stone, staining the top of it purple. That is why the top of amethyst is purple and the bottom is often white or clear.
Amethyst is a brilliant purple or violet variety of quartz, colored by the presence of iron or manganese when the crystals form. Amethyst crystals are hexagonal and can occur as tall prismatic crystals or short, stubby ones, and often have horizontal striations on their sides or faces. As with all varieties of quartz, Amethyst has a Moh's hardness of 7. It is found around the world, notably in Mexico, Brazil, Uruguay, Africa and Russia.
Amethyst Cathedrals—popular home decorating and Feng Shui elements—are actually giant geodes that formed in lava flows. When volcanic material forms, large bubbles are often trapped in the rock. Over millions of years, these bubbles form a coating of minerals from the surrounding soil on the inner surface. If water does not seep through this coating, fine crystals will form that eventually become the masses of crystals we see today.
Metaphysically, Amethyst is thought to enhance right brain activity and the powers of intuition, purify all levels of consciousness, cut through illusion, and aid channeling abilities.
Amethyst: SiO2, Silicon dioxide
Color: Purple, violet
Crystal habit: 6-sided prism ending in 6-sided pyramid (typical)
Crystal system: Rhombohedral class 32
Mohs scale hardness: 7 (lower in impure varieties)
Diaphaneity: Transparent to translucent
Specific gravity: 2.65 constant; variable in impure varieties
Optical properties: Uniaxial (+)
Refractive index: n? = 1.543–1.553 ne = 1.552–1.554
Birefringence: +0.009 (B-G interval)
Other characteristics: Piezoelectric