Amethyst has been considered a valuable gemstone since the dawn of humanity. Egyptians, in the time of ancient pharaohs, wore it as part of their most precious jewellery. Ancient Greeks believed amethyst could keep us safe from poisoning; many cups were coated with this mineral. Later, medieval European soldiers wore amethyst charms to protect them in battle and in Great Britain, beads of amethyst were found in numerous old Saxon tombs. It is yet believed that amethysts can cool hotheaded persons into calmness.

Seen on the rings of Christian bishops, it is an allusion to the description of the Apostles as "not drunk", yet it has not been said to keep them sober after heavy mead filled nights. This believed attribute of amethyst is what gave it its name: the Greek word "amethystos" is said to translate "sober", or better yet "not drunk" - a “not" +methustos, "drunk".

Ancient Greeks believed that Dionysus created amethyst. He was drawn to a girl called Amethyst, whom by desire and lust he could not resist. But she kept refusing his love. In madness, drawn by this longing, he tried to kill her, but the goddess Artemis changed her to a pure quartz statue (to protect her, or maybe she too was jealous of Amethyst’s beauty). Dionysus realized what had happened and shed many tears in remorse. He remained by Amethyst’s side, until one day he spilled wine over her clear quartz body, while moaning, and the wine turned her colour to purple. Thus the purple colouring of amethyst and its attribute is said to guard from drunkenness and excessive thoughts of desire.

Amethyst is an example of what is usually in gemology called allochromatic gems. This means its fine purple colour is by science considered an impurity. This is quartz coloured by traces of elements, in this case, amethyst mineral, by traces of iron.

The formula of all quartz mineral forms is SiO2. It has trigonal crystalline structure, as all quartz do, which means that the principal axis is one of threefold, and not sixfold symmetry.