Amethyst

The name amethyst comes from the greek amethystos — literally not drunk. The ancient Greeks took the meaning at its word. Drinking cups were sometimes carved from amethyst, and the red wine poured into them was said to look about the same colour as the cup itself. The wine could then be quietly diluted with water without the drinker noticing — the stone, not the dilution, was credited with keeping the room sober.

The Egyptians worked the mineral long before Europe attached stories to it. They cut amethyst as a gemstone and used it for intaglio engraved gems — small designs cut into the stone's surface, usually for sealing wax. The stone reached Rome along the same gem trade: a carved portrait of the emperor Caracalla in amethyst survived for centuries in the Treasury of Sainte-Chapelle.
The first-century Roman naturalist Pliny the Elder, in his Natural History, was unconvinced by the protective claim. He wrote that the falsehoods of the magicians would persuade us that these stones are preventive of inebriety, and that it is from this that they have derived their name.

Religious tradition picked up the stone in two distinct threads. The Hebrew Bible places it on the breastplate of the high priest: amethyst appears in Exodus 28:19 and 39:12 as one of the twelve stones set in the ḥoshen, the breastplate of judgement. The Hebrew name aḥlamah is rendered as amethystos in the Septuagint — the Greek translation of the Hebrew scriptures — fixing the modern identification of the stone.
The Christian thread runs through the New Testament. Acts 2:15 records Peter telling the crowd at Pentecost that the apostles are not drunk — a phrase that echoes the Greek meaning of the stone's name almost exactly. Anglican bishops still wear an episcopal ring often set with an amethyst as a direct allusion to that verse.

In the Middle Ages the stone widened its symbolic range. European soldiers wore amethyst amulets into battle, believing the stone could heal them and keep them cool-headed. It was treated as a symbol of royalty and used to decorate the English regalia — the crowns, sceptres and other ornaments of the monarchy. Tibetan Buddhists, on the other side of the trade routes, took it as sacred to the Buddha and made prayer beads from it.

The myth that anchored the amethystos name to a face came much later than the etymology itself. The French Renaissance poet Rémy Belleau (1528–1577) wrote a poem in which Bacchus pursued a maiden named Amethyste, who refused his affections — a literary invention later mistaken for ancient lore.

Until the 18th century, amethyst sat among the cardinal gems — the most valuable stones in the European tradition, alongside diamond, sapphire, ruby and emerald. That standing collapsed when extensive deposits were found in Brazil. A large geode from near Santa Cruz in southern Brazil was shipped across the Atlantic and presented at a 1902 exhibition in Düsseldorf, Germany. With supply now measured in tonnes rather than rare finds, amethyst lost most of its value and dropped out of that top rank.

Amethyst's only significant modern role is as a gemstone and ornamental material. The violet stone is faceted and set in jewellery as a semiprecious gem, typically in prong or bezel settings; channel settings are used with caution. Collectors and cutters prize specimens that show depth of colour and the red flashes that appear when light catches a well-cut crystal. Amethyst is the traditional birthstone of February, which gives the trade a built-in market for rings, pendants and earrings throughout the year.

Beyond cut stones, the trade in amethyst geodes — hollow rock cavities lined with crystals — is brisk. The hollow agates of southwestern Brazil and Uruguay regularly contain a crop of amethyst crystals on their inner walls, and the larger specimens travel from mine to gem show as polished display pieces. One geode at the American Museum of Natural History stands 3.7 metres tall and weighs four tonnes. Mineral collectors are the other half of this trade — single crystals, clusters and small geodes circulate continuously between dealers, fairs and private cabinets.

Commercial supply today rests on a few countries. Between 2000 and 2010, the largest production came from Marabá and Pau d'Arco in Pará, and the Paraná Basin in Rio Grande do Sul, both in Brazil. Zambia is the other major producer, with an annual output around 1000 tonnes.

Some commercial citrine — the yellow variety of quartz — is not natural at all but heat-treated amethyst. Exposure to heat cancels the irradiation effects that give amethyst its purple colour, leaving the crystal yellow or sometimes green. Much of the citrine, cairngorm and other yellow quartz on the jewellery market is, in the trade's own phrase, burnt amethyst.

Synthetic amethyst competes with the natural stone on the lower end of the gem market. It is grown by hydrothermal growth — silica feedstock dissolved in a hot alkaline solution inside a high-pressure autoclave, then crystallised onto a seed. The technique was first scaled commercially for clear quartz at Bell Laboratories in 1950, in response to a wartime shortage of natural Brazilian crystals for the electronics industry. Coloured varieties followed. Synthetic amethyst has the same chemistry and physical properties as the natural stone, but the specific twinning patterns found in natural specimens are absent. That absence is the main diagnostic for telling the two apart.