Amethyst.

Amethyst is a variety of Quartz, and the distinctive violet or purple colour of this crystal is caused by the presence of ferric iron - not, as is still widely reported, manganese.
             Amethyst can be found in Britain, in the Peak District area, and in Cornwall, for example on the beaches of Land's End and Marazion. There are also large deposits in the Americas, Africa and Australia, and almost all specimens offered for sale are imported.
             Crystal wands, which terminate in the usual Quartz formation of 6 facets, are often most deeply coloured near the tips, the bases often being very pale, even clear. The most valuable specimens are flawlessly clear and dark purple. So-called Chevron specimens (bearing V shaped bands of light and dark colour) are distinctive and attract novelty value. The tendency toward colour variation is an important factor to remember when considering acquiring an expensive Amethyst sphere. Some of the most perfectly shaped specimens are found lining hollow globular geodes, which are created when cavities in rock contain the mineral-rich fluid from which from which the Amethyst crystalises. Such cavities can be as small as a golf ball or large enough to make spectacular ornamental features.
              It can be distinguished from some minerals similar in appearance, by several factors, all of which relate directly to Quartz, its main constituent: it cannot be scratched by a steel knife, and it will scratch glass; its lustre is like that of glass; although its shank appears to be a Hexagonal prism, its crystalline structure is Trigonal - crystals occasionally have small extra facets at their tip, which are diagnostic of their true Trigonal nature.
              Sometimes Amethyst is subjected to treatment with high temperatures, when it becomes altered to Citrine (with which it is often found in nature).

Amethyst has long been associated with love and lovers. Roman wives valued it in the belief that its influence would ensure their husbands' fidelity. It is also reputed to draw the love of a worthy woman to a man. St Valentine is famed for wearing an Amethyst ring, engraved with the figure of Cupid. The Saint, who died in the year 270, is remembered on February 14, the day before Lupercalia. (Lupercalia was originally the Roman festival of Faunus, where women who wished to conceive were whipped by priests wearing nothing but the bloody skins of sacrificed goats. It was suppressed by Pope Gelasius in 494.)
             Faunus, Pan and Bacchus are all inextricably associated, and it is from a Greek legend that we learn of the origin of Amethyst. Once, Bacchus was so annoyed by Diana (a virgin huntress and Lunar deity) that he set his sacred tigers upon a maiden attending her shrine. To preserve the maiden, whose name was Amethyst, Diana petrified her in sparkling Quartz. Lamenting this virgin's demise, Bacchus poured a libation over the statue, which immediately became infused with the purple of the grape.
             The Greek name Amethyst literally translates as "without drunkenness". Goblets carved from this crystal cast a glorious hue over their contents, enabling even pure water to appear like wine. This eminently practical way of ensuring sobriety has been used since at least Roman times. Aleister Crowley, writing of the supreme sacrifice (entry into the Kabbalistic Abyss of Dissolution) which allows a high initiate to achieve union with all things, regards Amethyst as a powerful talisman of purification for a magician, stating: "It is the purity of the Exempt Adept which destroys for him the illusion or drunkenness of existence, and therefore enables him to take the great leap into the Abyss." (Liber 777).
              In the Middle Ages it was used as a charm to sharpen wits, and stay wide awake. In the Renaissance, Amethysts graven with the figure of a bear were talismans for personal protection. Since the 13th Century the Popes have received an Amethyst ring upon their investiture, at their death the ring, engraved with the figure of St Peter casting his fishing net, is smashed. Edward the Confessor established a long tradition among English monarchs, by using a crown bearing an Amethyst, at his coronation - symbolising the 'royal purple'.
              This jewel was mentioned in both Testaments of the Bible - worn by the High Priest in the Old, and as a foundation stone of the New Jerusalem. In Egypt it found favour as a beneficial stone, both generally and in relation to its power against the toxicity of alcohol. Many specimens are found in the tombs of the Pharaohs. Cleopatra's favourite piece of jewellery was an Amethyst ring, engraved with the figure of the Persian Sun god, Mithras.
             Early Arabian lore attests that Amethyst protects the wearer from nightmares. To dream of this jewel indicates that peace of mind, well-being and contentment will come.