Amethyst: Properties, Facts and Photos

Amethyst is the purple variety of quartz and one of the world’s most recognisable minerals. This article explores how it forms, the source of its colour, its history, and common misconceptions.

What is Amethyst?

Amethyst is the purple variety of the mineral quartz whose colour comes from impurities of iron. However, iron alone does not cause the crystals' colour to change.

For the transformation to take place, the colourless quartz crystals must be exposed to heat, which in nature comes from radiation.

When colourless quartz crystals are exposed to natural radiation, colour centres can form within the mineral's crystal structure. These impart different hues which leads to the formation of varieties such as amethyst, citrine, and smoky quartz.

The heat generated when radiation is absorbed plays an important role in activating and stabilising the colour centres, which causes the transformation from colourless quartz to purple quartz.

The process occurs over long periods of time but can be replicated in a controlled environment.

Many amethyst quartz crystals are heated in industrial-sized ovens. The heating gradually reduces the amount of iron, disrupting the mineral's chemical composition and altering its colour.

Heat treatments can remove unwanted wisps of colour, lighten, darken, or change a stone's colour completely.

Much of the world's commercial-grade citrine is heated amethyst.  The reason for doing this is because natural citrine is quite rare.
When heated to 450°C (842°F), amethyst crystals turn yellow. Increase the temperature, and they turn orange and then orange-brown. The final colour is determined by temperature and the length of time the crystals are heated.

It's usually quite easy to tell natural citrine from heated amethyst. Heated amethyst tends to be a deeper shade of yellow or burnt orange. The crystals in the photo above are heated amethyst. Although the colour of natural citrine can vary, the shade is rarely as intense and is often uniform throughout the stone.

In natural amethyst, white quartz or subtle shades of orange or yellow are sometimes visible towards the base of the crystal. This is because there's less iron in the lower section. The depth of colour towards the tip is often much stronger. It's believed this is because of the mix of iron in the water as the crystal grows.

Prasiolite is a rare green variety of quartz. Most commercial-grade prasiolite is produced by heating amethyst. It's often referred to as green amethyst, which is a misnomer.

Amethyst is a geological name for the purple variety of the mineral quartz.  Quartz in any other colour cannot be amethyst.

Meaning of the Word Amethyst

The meaning of 'amethyst' comes from the belief that it can counter the effects of alcohol. This came about because ancient Greek philosopher Theophrastus, and Roman author and naturalist Pliny the Elder both likened its colour to wine.

Theophrastus named it 'amethystos', which comes from the Greek words 'not' and 'intoxicate'.

This also seems to be the reason why amethyst became popular with the church. A single amethyst gemstone is often used in ecclesiastical rings worn by bishops and cardinals and can also be found in other religious garments.

What Colour is Amethyst?

Amethyst, which is one of the world's oldest gemstones, is well-known for its rich purple colour. However, the shade can vary significantly.

The finest gem-grade stones have a reddish-purple colour, deep saturation, and no colour zoning. Amethyst crystals in darker shades of purple are also popular, but if too dark, the stone can look almost black.

The colour purple, once known as magenta, doesn't exist naturally. It can only be produced by combining red and blue. Therefore, purple is a perceived colour invented by our eyes and brain.

A rainbow exhibits the full spectrum of colours yet doesn't include purple. This short video explains why.

Colours have long been known to affect mood, behaviour and even emotions. Except for the plant kingdom, purple is rare in nature. Only a small number of purple-coloured minerals exist.

Throughout history, purple has been associated with religion, royalty and wealth. Today, it's also associated with magic, mystery and fantasy.

The suffragettes wore purple, white, and green. Purple stood for loyalty and dignity, white for purity, and green for hope.

To the ancient Egyptians and Romans, amethyst was rare, valuable and highly sought after.

Traces of amethyst first appeared in the form of a dye during the Neolithic Age (10,000 BC). Paintings of animals and the outline of human hands have been found on cave walls in France.

The dye used to create these was made from sticks of manganese and hematite powder. The paintings date from 16,000 to 25,000 years BC. 

Until 1856, the colour purple could only be produced from natural dyes, so it was rarely seen. In the 15th century BC, it was produced from the mucous of the murex sea snail.

Known as purple dye murex or Tyrian purple, it was named after the Phoenician city of Tyre, modern-day Lebanon.

Thousands of snails were crushed to produce an ounce of dye. In 2008, Tyrian purple was recreated using the original formula. 12,000 sea snails created just enough dye to colour a small piece of material.

Only after huge reserves of amethyst were found in South America in the 1800s did it become a more affordable gemstone. Today, this type of quartz can be found in many countries around the world, including the United Kingdom.

The History of Amethyst?

Altering the properties of stones to enhance or change their colour has a long history.  Theophrastus, ancient Greek philosopher [c.370-285 BC] documented in his treatise Theophrastus On Stones;

"amethyst loses its colour in the fire like the sapphire and emerald".

He remarked that amethyst is similar in colour to wine and said along with rock crystal, it could be found by "dividing other stones."

He says quartz and amethyst can be found in veins, cavities or lining the interior of geodes. Crystals are only revealed when rocks are broken open.

Approximately three hundred years later, ancient Roman author, naturalist and philosopher Pliny the Elder wrote about "giving quartz the colour of emeralds" and "how to change one gemstone into another". This is believed to refer to the change of colour when some stones are heated.

Amethyst was highly prized in ancient Egypt. The earliest reference to this mineral was 3100 BC.

It's believed that in the past, translucent stones of a similar colour were grouped together. Amethyst would have been with fluorite, corundum (blue corundum is sapphire) and possibly tourmaline.

Pliny also compared the colour of amethyst to wine. In his encyclopaedia Naturalis Historia (Natural History), he writes;

"We will now commence with another class of precious stones, those of a purple colour or whose tints are derived from purple. To the first rank belongs the amethystos".

He goes on to say,

"All of these stones are transparent and of an agreeable violet colour and easy to engrave. Those of India have in perfection the very richest shades of purple and it is to attain this colour that the dyers in purple direct all their endeavours"

Historians use translations of the original text to work out what stones Pliny is referring to.

Corundum is exceptionally hard, so it would not have been easy to engrave. Therefore, it's believed it was not included in the group known as amethystos.

This is supported by Pliny's description of this group of stones in which he says, "They have a fine mellowed appearance to the eye and not dazzling the sight like the colours of the carbunculas (garnet)."

He says, "The colour of one is almost hyacinth whilst another borders on crystal with the purple gradually passing off into white."

He talks about it having little value because when viewed sideways and held up to the light, fine amethyst (a reference to corundum or blue sapphire) should always have a purple brilliance like that of the carbunculus, "slightly inclining to a tint of rose". 

Pliny said the name amethystos, according to "some authorities" comes from Greek for "not" and "to intoxicate," which stems from it being "a supposed preservative against inebriety."

It's believed that he's not referring solely to the group of stones known as amethystos, but to all groups of stones that are purple or whose tints are derived from purple. That includes corundum, fluorite, and possibly garnet, amongst others.

Amethyst is believed to have been the third stone in the third row of the high priest breastplate. This religious garment was worn by the Jewish high priest during biblical times.

In the Middle Ages, amethyst was believed to encourage celibacy and symbolise piety, so was favoured by the church.

More recently, a large amethyst crystal can be seen in the Royal Sceptre, part of the British Crown Jewels. The stone is mounted below a diamond-encrusted cross with an emerald in the centre. King Charles III held the sceptre in his right hand during his coronation. 

Amethyst - The Greek Myth

Countless articles discussing the origins of the name 'Amethyst' cite a myth from Greek mythology. The only known reference to this mineral in Greek mythology is a stone given to Dionysus (Greek God of wine) by the titan Rhea to preserve the wine-drinker's sanity.

French poet Remy Belleau published a book of poems in 1576. One poem bore a striking resemblance to this apparent Greek myth. Published less than ten months before his death, nothing suggests it was based on text from Greek mythology.

Bacchus is the name adopted by the Romans for Dionysus, the Greek God of wine.

"Bacchus was pursuing a maiden named Amethyste who refused his affections. Amethyste prayed to the gods to remain chaste, a prayer which the goddess Diana answered, transforming her into a white stone. Humbled by Amethyste's desire to remain chaste, Bacchus poured wine over the stone as an offering, dyeing the crystals purple"

In recent years, many different versions have appeared. Each time it's republished, the author claims incorrectly that the myth comes from Greek mythology. No factual evidence exists to support any such myth having existed.

This is a perfect example of how inaccurate information spreads. So much of what is written about crystals, especially online, has been plagiarised from other sources.

Before republishing the information, few people check whether it's factual.

Article Pictures

The amethyst geode at the top of this article, the citrine crystals (heated amethyst), and the smoky quartz are from our collection. 

The amethyst in the next image: Courtesy of Stan Celestian.

Both geodes are on display in the Smithsonian Museum of Natural History, Washington, D.C. Photo: Stone Mania

The amethyst in the next two photos: Courtesy of Ron Wolf and Stan Celestian.

The ring is featured in the Smithsonian Magazine. The image links to the full article.

Pop-up photos
Colourless quartz: Courtesy of Stan Celestian. Citrine: Courtesy of Steve Blyskal.

The snow quartz and fluorite tumbled stones are from our collection.