Amethysts. Brazil (6.22, 9.18), Zambia (8.52) // Brazil (4.40, 3.61, 6.41, 6.38). Photo © Joel E. Arem, PhD, FGA. Used with permission.
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People have prized amethysts for thousands of years. The Ancient Egyptians carved these durable gemstones into the shapes of animals, perhaps as protective amulets. The Ancient Greeks created amethyst carvings and jewelry pieces as well as one of the most enduring bits of amethyst folklore — its supposed power to prevent drunkenness. To learn more about the myths and legends associated with this gem, consult our symbolism article.
The drill hole and signs of wear on this carved amethyst figure of a female monkey holding its baby suggests this was worn as an amulet. Egypt, Middle Kingdom, 12th Dynasty, 1981-1802 BCE, 3.5 cm. Gift of Norbert Schimmel Trust, 1989. Metropolitan Museum of Art, New York. Public Domain.
Transparent, eye-clean amethysts suitable for faceting occur abundantly. Gem cutters can facet amethyst with almost any design suitable to its size and color tone and saturation. For example, Barion cuts work well for large, lightly colored stones, while shallow designs and fantasy cuts work well for darker gems. Skilled faceters can also experiment with custom designs.
Custom octagon-cut amethyst, medium-dark reddish purple, 19.35 cts, 16.4 mm, Four Peaks Mine, Maricopa Co., Arizona. © The Gem Trader. Used with permission.
Amethysts can serve as beautiful centerpieces as well as accent or side stones in jewelry.
Identifying Characteristics
Amethysts may appear similar to other popular transparent gemstones such as sapphires, spinels, and rhodolite garnets. However, since these gems occur rarely in purple colors, you’re more likely to encounter amethysts misidentified as these rarer and more expensive stones. Nevertheless, these gems have notable differences in both optical and physical properties. Sapphires, spinels, and rhodolites all have higher refractive indices (RI), and spinels and rhodolites are also isometric. They also all have greater specific gravity values.
Natural amethyst receives its color from the presence of iron and other trace elements as well as natural irradiation. Amethysts may show color zoning, both uneven (unintentional) color distribution as well as color bands (intentional).
What’s the Difference Between Amethyst and Ametrine?
Ametrine is a variety of quartz with two distinct color zones, purple and yellow. These layers result from stop-and-start growth during the formation of the crystal underground, a process known as twinning. Since purple quartz is amethyst and yellow quartz is citrine, this means such a gem consists of amethyst and citrine zones, hence the name.
Usually, faceters will cut ametrines into rectangular emerald-cut shapes to highlight the two colors. However, some gem cutters may opt for designs that combine the zones, creating interesting flashes of color.
Synthetics
Amethysts can be grown hydrothermally in labs, and manufacturers can also create them by bombarding specially prepared smoky quartz with gamma rays.
Since natural amethyst is so abundant and inexpensive, little incentive exists to purchase synthetics. However, synthetic rough material is sometimes sold as natural rough.
Enhancements
A variety of treatments can change the color of amethysts. However, strictly speaking, only those gems with lilac to deep purple colors remain amethysts. All others simply become different colored varieties of quartz. For example, amethysts heated to yellow or red-orange colors are, by definition, citrines.
Once gem treatments turn amethysts into any color besides purple, they cease being considered amethysts. Color-enhanced amethyst clusters, Brazil. Photo by Jarno. Licensed under CC By 2.0
Heat treatments can lighten amethyst, turning it green, blue, or yellow-orange. This undetectable treatment has excellent stability. When heated to 400-500º C, amethysts may turn brown, red, and sometimes a green color. These green quartz gems are known as prasiolite.
Irradiation plus heating may also produce brown, orange, and yellow hues.
Sources
Today’s major sources are Brazil, Bolivia, Uruguay, and Zambia. Brazil can produce stones of large size but generally moderate color. They often show uneven color, despite the best efforts of cutters to minimize it. Many gem enthusiasts prefer the usually smaller but more richly colored stones from Zambia as well as, more recently, Uruguay.
Four Peaks, Arizona produces top-quality facetable amethyst.
These three amethysts from Four Peaks, Arizona have a blue component to their striking, deep purple color. 7.0-ctw, 10 x 8mm. © All That Glitters. Used with permission.
Other notable gem-quality sources include the following:
- Australia; India; Madagascar; Mexico; Morocco; Namibia; Nigeria; Russia; South Korea.
- United States: Georgia; North Carolina.
This color-zoned slice of amethyst comes from an unusual stalactitic growth. 8.2 x 7.5 x 0.3 cm. Jalgaon, Maharashtra, India. © Rob Lavinsky, www.iRocks.com. Used with permission.
Stone Sizes
In terms of size, amethyst is one of the exceptions of the quartz family. Most quartz can grow quite large and be cut into gems weighing thousands of carats. However, there are few clean examples of amethysts of 100 or more carats.
Amethysts of all sizes can make beautiful jewelry, like this owl motif pendant. © CustomMade. Used with permission.
Although transparent amethyst occurs commonly, this rarely happens in very large masses. The fine gems at the Smithsonian Institution (Washington, DC) are exceptional, such as the 1,362-ct Brazilian stone and the 202.5-ct stone from North Carolina.
Trade Names
- Siberian amethyst: dark purple color with flashes of red and/or blue.
- Golden amethyst: ametrine.
Misnomers
You might encounter amethysts heated to a brownish yellow color sold as “Madeira topaz.” Stones with lighter shades are sometimes sold as “Palmyra topaz,” while amethysts heated to a reddish color sometimes receive the name “Spanish topaz.”
Other gem species sometimes receive names connecting them to amethyst. For example, violet sapphire is sometimes referred to as “oriental amethyst.” Kunzite is sometimes referred to as “lithia amethyst.”
All these names are erroneous and misleading. Avoid using them and be alert if vendors use these monikers without explaining the gem’s true identity. As quartz, amethysts belong to a species distinct from topaz, sapphire, and kunzite.
Consult our List of Gemstones with False or Misleading Names for more examples.
Care
Lapidaries can use amethysts for any type of jewelry setting, including rings, as well as carvings, beads, and other decorative objects.
Although quartz gems are very durable, amethysts are sensitive to extreme heat. Furthermore, inclusions can make these gems susceptible to shattering in ultrasonic cleaners. Avoid mechanical cleaning systems and stick to a soft brush, mild detergent, and warm water, instead.
See our Gemstone Care Guide for recommended cleaning methods.
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