Amethyst baby geodes (1.5-4 kg) from Rio Grande do Sul, Brazil, in AB quality (light to medium dark)

Amethyst is a violet variety of the mineral quartz (SiO₂) and is the most sought-after stone from the quartz group. Etymology The name comes from the Greek αμεθυστος (amethystos). Amethyst was already known to the Egyptians, Etruscans and Romans, and Pliny the Elder already described amethyst. In ancient China, small gems were cut from amethyst. Amethyst was also highly prized in Europe during the Middle Ages. Known as the bishop's stone, amethyst once enjoyed popularity among church dignitaries due to its alleged magical powers. It was the symbol of lovers, the stone of temperance, and a protector against sorcery and witchcraft. Jacob van Maerlant explains that the stone drives away drunkenness. The Greek name is believed to signify "against intoxication," as drinking wine from an amethyst cup would not lead to intoxication. Origin: metamorphic, hydrothermal, alluvial The crystals always grow on a substrate; the prisms are often poorly developed, and therefore the crystal points of amethyst predominate. Here the colour is also the most powerful. These parts are knocked off, that is, broken off for further use. By firing at a temperature between 470 and 750 degrees, light yellow, reddish brown, green or colourless varieties are created. There are amethysts that gradually fade in daylight. The original colour can be restored with radium irradiation. The colour is caused by iron in combination with ionising radiation. Amethyst is less attractive in artificial light. Occurrence Brazil has been mining amethyst deposits since the Middle Ages, primarily in Bahia, Minas Gerais, and Mato Grosso. Recently, the so-called ametrine, an amethyst-citrine, has been mined in Bolivia, in which the violet and yellow colours alternate, but the transition between the colours is sharply defined. Amethysts are also known in the United States, namely in Montana, Maine, Georgia and Arizona. Canada, Mexico, Bolivia, India, Myanmar, Japan, China, Korea, Sri Lanka, Zimbabwe, Congo and Australia are also important producers. Russia finds amethyst in the Urals, Yakutsk, and on the Kola Peninsula, among other places. Amethysts are also found in Armenia, Germany, the Czech Republic, Slovakia, Bulgaria, Switzerland and Ireland. Amethyst only rarely forms larger, pure crystals. The British Museum has a unique cut stone of 343 carats. Other, smaller stones weigh less; they usually come from Brazil. The Smithsonian Institution in Washington D.C. even has a cut amethyst from Brazil weighing 1,362 carats and one from North Carolina weighing 202.5 carats. Amethysts are often used in state jewels, such as Catherine the Great's sceptre and the British crown sceptre.