Amethyst: A Purple Quartz Gemstone Guide

History

Amethyst, a captivating gemstone with a rich history, is a variety of quartz that has been prized for thousands of years. It is the February birthstone and is also used to celebrate the 6th and 17th wedding anniversaries. Ancient Egyptians carved amethysts into animal shapes, possibly as protective amulets. The Ancient Greeks believed amethyst could prevent drunkenness, with the name 'amethystos' meaning 'not drunk' in Greek. The gemstone has been associated with romance and spirituality, with Christian scholars referring to it as "the bishop's stone" for its power to provide clarity and sobriety, and Buddhist monks using it to make prayer beads. It is a gem that is both beautiful and affordable, making it suitable for both high-end designer pieces and everyday jewellery.

Mineral Origins

Amethyst is a crystalline quartz, found in a variety of locations around the world. Major sources include Brazil, Bolivia, Uruguay, and Zambia. Brazil produces large stones, often with moderate colour, while Zambia and Uruguay are known for producing smaller stones with richer, darker colours. Amethyst can also be found in the United States, including in Arizona, and in Canada. The gem is typically found in pegmatites and veins, and in geodes within alluvial deposits. The colour of amethyst is due to the presence of iron and other trace elements as well as natural irradiation. Amethyst may exhibit colour zoning, with uneven colour distribution or intentional colour bands.

The 4 C's

Colour

The most important factor in determining the value of an amethyst is its colour. The finest amethyst displays a strong reddish-purple to purple hue, with no visible colour zoning when viewed from above. Any brownish or bronze-coloured tints or noticeable colour zoning will lower its value. The intensity of the colour is important, with dealers preferring strongly saturated reddish purple to dark purple, but not so dark that it reduces brightness or appears black under dim lighting. Lighter, pastel shades of amethyst are sometimes called "Rose de France". Amethyst is sensitive to lighting, appearing deeper purple in evening light and cooler grayish-blue in daylight.

Clarity

Most faceted amethyst on the market is "eye-clean," meaning it lacks inclusions visible to the naked eye. Minor inclusions may be overlooked if the gem has a rich colour. However, visible inclusions in pale gemstones will reduce their value. Amethysts with visible inclusions but attractive colour are often cut as cabochons or fashioned into beads. African amethyst, particularly from Zambia, tends to have more inclusions than Brazilian material, though its saturated raspberry colour can still be acceptable in a faceted stone.

Carat

Amethyst is available in a wide range of sizes, and unlike some other coloured gemstones, its price per carat does not increase dramatically with larger sizes. This makes it a popular choice for large centre stones in jewellery. Both small and large amethysts can have strong colour, making it easier to match sets of differently sized stones.

Cut

Amethysts are cut into a variety of shapes, including rounds, ovals, pears, emerald cuts, triangles, marquises, and cushions, as well as custom and freeform shapes. Facet patterns include brilliant cuts, step cuts, and mixed cuts. Skilled cutters may also create fantasy or designer cuts, with concave facets. The quality of the cut impacts the beauty and brilliance of the gem, with well-cut amethysts reflecting light evenly and sparkling in a lively way.

Be Aware of

Enhancements

Amethyst can be heat treated to lighten its colour or change it to citrine or other colours. Heat treatment is usually permanent and will not fade. Very dark amethyst can be lightened with heat treatments, but heating amethysts to 400-500° C may turn it brown, red or green, which is then known as prasiolite. Lower quality, light-coloured amethysts and quartz may be dyed purple.

Simulants

Amethysts may look similar to sapphires, spinels, and rhodolite garnets, though these are less likely to be found in purple colours. These gemstones have different optical and physical properties such as higher refractive indices and specific gravity values.

Synthetics

Synthetic amethysts can be grown in labs, and also created by bombarding specially prepared smoky quartz with gamma rays. Since natural amethyst is abundant and relatively inexpensive, there is little incentive to purchase synthetics, though synthetic rough material is sometimes sold as natural rough. Gemologists can easily distinguish between natural and synthetic amethyst.

Final Thoughts

Buying Tips

When buying amethyst, it is important to understand the difference that colour makes, as pale colours are more affordable than strong reddish purple tones. Do not compromise on cut, ensuring the gem sparkles evenly and reflects light well. It is advisable to work with a trusted jeweller who has gemological knowledge. For significant purchases, an independent laboratory report can verify that the amethyst is natural. Though origin does not add value, some prefer the colour of amethysts from specific locations.

Jewellery Care

At 7 on the Mohs scale, amethyst is durable enough for everyday wear, but it can still show wear over time and may require repolishing. It is also sensitive to extreme heat. Clean amethyst jewellery with warm soapy water and a soft brush, avoiding mechanical cleaning systems and ultrasonic cleaners. Clean regularly to prevent build-up of cosmetics and dirt that can affect brilliance.

Sources

Cited gemological sources
Authority	Title	URL
GIA	Gemological Institute of America, Amethyst encyclopedia + quality factors	gia.edu/amethyst
IGS	International Gem Society, Amethyst value, price, and jewelry information	gemsociety.org/article/amethyst-jewelry-and-gemstone-information
AGTA	American Gem Trade Association, Amethyst (February birthstone) reference	agta.org/gemstones/amethyst

Frequently asked questions

What is Siberian amethyst?

Siberian is a trade term for top-grade amethyst with a deep, saturated reddish-purple and flashes of red and blue, not necessarily from Siberia. It describes the finest color rather than an origin. Most amethyst today comes from Brazil, Uruguay, and Zambia, with Zambian and Uruguayan stones often richer and darker.

What is the difference between amethyst and ametrine?

Ametrine is a single quartz crystal containing both amethyst purple and citrine yellow in distinct zones, formed where temperature differed across the growing crystal. Essentially all natural ametrine comes from the Anahí mine in Bolivia, which makes it far scarcer than either amethyst or citrine alone.

What is the difference between natural and lab-grown amethyst?

Both are real amethyst, but lab-grown is made in a factory rather than in the earth. Because natural amethyst is abundant and inexpensive, there is little reason to buy synthetic, yet lab rough is sometimes passed off as natural. Gemologists can tell them apart, so ask for a report on important purchases.

How can I tell if amethyst is real?

Natural amethyst almost always shows uneven colour, with the purple concentrated in angular zones or at the crystal tip. Glass imitations are uniformly coloured and often contain round bubbles. Synthetic amethyst is chemically identical to natural and cannot be separated at home, though it is worth far less.

Are green and pink amethyst real amethyst?

Both are quartz, but neither is amethyst in the strict sense. Green quartz, sold as prasiolite or green amethyst, is almost always heat-treated amethyst and the name is discouraged in the trade. Pink amethyst is a genuine natural pale pink quartz from Argentina, usually sold as geode slices.

Is amethyst heated or treated?

Often, yes. Heat is commonly used to lighten overly dark amethyst or to even out color, and it is stable and accepted. Strong heat can also turn amethyst into citrine or green prasiolite. Some pale quartz is dyed. For a significant stone, a lab report confirms whether the color is natural.

What makes amethyst valuable or not?

Color drives amethyst value far more than size. The most prized is a strong, even reddish-purple to deep purple with no visible color zoning and no brownish tint. Pale, washed-out stones, sometimes sold as Rose de France, sit at the lower end. Because amethyst is abundant, even large fine stones stay affordable.

Why is amethyst so much cheaper than other purple gems?

Amethyst is one of the most abundant fine gemstones, found in large, clean crystals worldwide, so supply keeps prices low even for rich color and big sizes. Purple sapphire or spinel of similar look costs far more because they are far rarer. With amethyst you get strong color and size for a modest price.

Why is amethyst so cheap now?

Large deposits in Brazil, Uruguay, and Zambia turned a historically rare stone into an abundant one during the nineteenth century. Before that amethyst ranked alongside ruby and emerald in value. The collapse is a supply story, not a quality one, and fine deep Uruguayan material still commands real prices.

Is amethyst durable enough for everyday rings?

Yes. At 7 on the Mohs scale amethyst resists everyday scratching and suits daily wear, including rings. Over years it can dull and may need repolishing. Clean it with warm soapy water and a soft brush, avoid ultrasonic and steam cleaners, and keep it away from extreme heat.

Does amethyst fade in sunlight?

It can. Amethyst is light-sensitive, and long, repeated exposure to strong sunlight or heat can gradually pale its purple. This is easy to avoid. Wear and store it away from prolonged direct sun, and keep it from high heat. Normal daily wear and indoor light do not noticeably harm the color.

Can amethyst go in an ultrasonic cleaner?

Usually yes, since quartz is 7 on the Mohs scale and reasonably robust. Avoid it if the stone is visibly included or fractured. Steam cleaning is the greater risk, because sustained heat can lighten or brown the colour in the same way sunlight does.

Which month is amethyst the birthstone for?

February. Amethyst has held the February position on the American list since 1912, and the association runs back through medieval and classical sources well before that. It is also the traditional gift for a sixth wedding anniversary.

What does amethyst symbolise?

The name derives from the Greek amethystos, meaning not intoxicated, and classical belief held that the stone prevented drunkenness, which is why wine vessels were carved from it. That reading carried into Christian usage as a symbol of sobriety and clear judgement, and it remains the stone's dominant association.