Amethyst

Amethyst is the purple-to-violet variety of quartz, the silicon dioxide mineral, and its colour comes from iron impurities acted on by natural irradiation. Heating turns it yellow-orange or brownish, and long exposure to strong light can fade it. It grows as pointed crystals, clusters and geodes; much of the world's supply comes from large geodes in the volcanic rocks of southern Brazil and neighbouring Uruguay. The name comes from a Greek word meaning 'not intoxicated': the ancient Greeks wore the stone and carved drinking vessels from it in the hope of staying sober, Anglican bishops' rings are often set with it in allusion to the Apostles' sobriety at Pentecost, and it is the birthstone of February. In Cunningham's magical lore it is above all a stone of peace, placed beneath the pillow against insomnia and nightmares, worn for courage and as a protective amulet, especially by travellers, set on meditation altars, kept with divination tools to sharpen psychic awareness, and exchanged between lovers. Hall describes it as a strongly protective and calming stone that supports meditation, intuition, memory and restful sleep, and connects it with sobriety and with overcoming addiction.