Aquamarine vs. Amethyst

By Claudia S. Copeland, PhD

Prince Charles and Camilla Bowles Wearing Amethyst

Aquamarine jewelry and amethyst jewelry are two of the most popular of all gemstone jewelry, with mystical colors that resonate tranquility. Aquamarine ranges from ice blue to cerulean sea green, while amethyst ranges from pale lilac to deep twilight violet. Their winter-palette hues are where their similarity ends, however—these beautiful minerals are completely different by nature. Aquamarine is a beryl, like morganite and emerald, and amethyst is a quartz, like citrine, prasiolite, smoky quartz, and rose quartz.

Jewels of Wine and the Sea

In spite of their mineralogical differences, aquamarines and amethysts are both prized for their cool colors, evocative of serenity.  This shared association may be related to a connection of both stones to liquid: in the case of amethyst, that liquid is wine, in the case of aquamarine, it is the vast blue waters of the sea.

Amethyst and Dionysus

Modern Day Dionysus, Not Too Pretty!

The amethyst has been thought to be protective against drunkenness since antiquity, with amethyst specifically mentioned as protecting Dionysus from drunkenness, keeping the god calm and cool as the wine drinkers around him grew deliriously disinhibited with intoxication.  The name amethyst derives from the Greek amethystos, meaning “not drunken”, and it has been common practice to wear amethyst jewelry while drinking to maintain sobriety. Amethyst goblets and amethyst rings have even been carved for this purpose.

The most well-known mythology on the origins of amethyst is not a Greek or Roman myth, but a Renaissance era poem that was thought for many years to be based on an ancient myth: Remy Belleau’s L’Amethyste, ou les Amours de Bacchus et d’Amethyste.  In this poem, Bacchus (the Roman equivalent of Dionysus) was in an angry mood, and decided to order his tigers to attack the next person he saw.  An unfortunate maiden named Amethyst was on her way to worship Diana, when she happened upon Bacchus and his tigers.  To protect her from the horrific fate of being clawed to death by the fearsome beasts, Diana intervened and turned her body into pure, clear stone.  When Bacchus saw this, he poured wine over the stone as an offering and expression of his remorse, dying the clear stone a beautiful purple.  

Aquamarine and the Deep Blue Sea

If any gemstone is reminiscent of the tranquility of the ocean, it is the pale blue aquamarine.  The name itself means “waters of the sea”, and it was carried by mariners to bring them luck and banish fear when sailing. Sea voyages were extremely dangerous in the past, and one can only imagine ancient sailors’ dread of drowning; many did not even know how to swim. Wearing aquamarine rings believed to be protective would be extremely valuable in its ability to cool this fear.  In light of evidence that the color blue itself has a calming effect, simply gazing at the serene blue of an aquamarine bracelet could help calm the terror, and give some sense of control to people setting off in a ship made tiny by the vastness of the deep and powerful ocean.

Aquamarine, Cousin of Emeralds

So, where does this beautiful stone get its pale blue color?  Aquamarine, like emerald, is a beryl.  Pure beryl [Be3Al2(SiO3)6], however, is clear.  It is the impurities in the beryl crystal that give it its azure color.  While emeralds owe their deep green to tiny amounts of chromium or vanadium, the aquamarine gets its delicate color from a substance with a much tougher reputation: iron.

While iron metal is heavy and strong, suitable for weapons and frying pans, when iron atoms lose electrons, they change from uncharged metallic atoms into salty, colorful ions (atoms with a charge due to gaining or losing electrons). Ions in small amounts can lend delicate colors to an otherwise clear crystal, and iron ions are no exception.  Iron ions can take the form of Fe2+ (when the iron atoms have lost two electrons) or Fe3+ (when the iron atoms have lost three electrons). In the case of aquamarine, it’s iron ions of the Fe2+ variety that provide the blue color, but Fe3+ can also be present. Fe3+ colors beryl yellow. When a bit of yellow from Fe3+ combines with the blue of Fe2+, it lends a slightly green cyan shade to the beryl, resulting in highly prized “sea foam” blue-green aquamarines.

Amethyst, Queen of Quartz

Amethyst, the most valuable variety of quartz (SiO2), and popular in amethyst earrings also gets its color from iron ions. However, the type of ion that lends amethyst its regal color is very different from those encountered in most gems: Fe4+, a highly unusual iron ion that has lost four electrons. 

The structure of quartz allows ions to either substitute for the silicon ions in the silicon dioxide crystal lattice or insert themselves in between the main repeating crystal.  When Fe3+ ions within the crystal structure are exposed to natural gamma ray radiation from surrounding rocks, it can knock them out of the main crystal and into the spaces between the main crystal elements, called interstitial spaces.  As this happens, the Fe3+ ions lose another electron, transforming them into Fe4+ ions, the highly unusual ions that absorb certain wavelengths of light to lend amethyst its striking purple color. 

Amethyst vs. Aquamarine: Hardness and Durability

Hardness in a gemstone is its ability to scratch another solid.  Hardness in gems is measured by the Mohs scale, which orders different minerals from 1 to 10 according to their ability to scratch other minerals.  For example, sapphires, which have a hardness of 9 on the Mohs scale, can scratch emeralds, which have a hardness of 8, but diamonds, the hardest gems of all, at 10 on the Mohs scale, can scratch sapphires. 

Hardness is important in jewelry because, during ordinary wear, jewelry can rub up against various solid surfaces.  If the gemstone is softer than the solid it is rubbing against, it can be scratched by that substance.  Soft gems are at high risk of becoming scratched if they are set in rings, since the hands come into contact with solid surfaces on a regular basis.  One of the most dangerous solids for gemstones is dust.  This is because ordinary dust contains a good deal of quartz, which at 7 on the Mohs scale is quite hard.  Gems softer than 7 are best worn in settings like earrings and necklaces, which do not come into contact with many surfaces.  Or, they can be worn on the hands but only with care, on special occasions.

Aquamarines, with a hardness of 8, are safe to wear as any type of jewelry—an aquamarine ring can rub up against the insides of a dusty purse all day and be none the worse for wear.  Exposure to light and/or humidity is also not a problem, although exposure to high heat is not a good idea, since it could change the color of your stone, especially if it has never been heat pre-treated. Since aquamarine rings and aquamarine bracelets are as safe to wear as aquamarine earrings or an aquamarine necklace, you have much more freedom in choosing a jewelry design.  It’s even hard enough for engagement rings. The aquamarine engagement ring is a beautiful and unique alternative to a diamond that is entirely suitable for everyday wear on the hand.

Amethysts, being a type of quartz themselves, have the same hardness as the quartz in dust.  While two minerals of the same hardness can scratch each other, they can only do so with difficulty. Amethyst is a fairly safe mineral to wear, and an amethyst ring can be worn in everyday settings, although it is perhaps not the best choice for an engagement ring, which will be worn 365 days/year.  Prolonged light exposure can fade amethysts, and sudden heat changes can cause the stones to fracture.  Amethysts can also be damaged by household chemicals, so it’s best to take off your amethyst bracelet or rings before cooking or cleaning.

Amethysts and Aquamarines Through the Ages

The Dom Pedro Aquamarine of the Smithsonian Institution 

Amethysts and aquamarines have a rich and varied history, being worn by royalty and ordinary people paying dearly for their purported protective benefits.  They have also been used in sculpture. The largest cut aquamarine is the world-famous Dom Pedro aquamarine, now housed at the Smithsonian.  Also housed at the Smithsonian is one of the largest cut amethysts in the world, a 401.52 carat stone of superb clarity.  Both aquamarines and amethysts have been treasured from the earliest years of history.

Amethyst and Aquamarine in Antiquity

Amethysts have been worn as jewelry since ancient times.  Among the oldest amethyst jewelry is a carved amethyst necklace dating from 2,000 BCE. In addition to preventing intoxication, the ancient Greeks believed that amethysts kept their wearers clear-headed during battle and business dealings. Ancient Asian civilizations also prized this gem. In the Torah/Bible, the amethyst was one of the stones in the breastplate of Aaron, which included one stone for each of the 12 tribes of Israel.

Aquamarine was probably also represented on the breastplate.  Only the more general “beryl” is specifically mentioned, however, and this could have referred to another blue-green stone, such as malachite.  The specific stone is still a matter of speculation among scholars.  However, what is known is that aquamarine was a well-known mineral, and valued gemstone, in ancient times. Aquamarines were imported into the Roman empire from faraway lands, and the mariners of antiquity supposedly wore amulets with carvings representing the god Neptune/Poseidon for protection.  A beautiful carved aquamarine intaglio of Roman empress Julia Domna dating from AD 200-210, housed at the Metropolitan Museum of Art, is testament to the ancient admiration of this stone.

Amethyst and Aquamarine in the Middle Ages

In the Middle Ages, amethysts and aquamarines were worked into both jewelry and weapons.  They were also incorporated into sculptures, such as a late 10th to early 11th century statue of Sainte-Foy (Saint Faith) housed in her namesake church in Conques, France, a popular medieval pilgrimage stop. They were also mentioned in religious texts, such as the assertion that the foundations of the walls of the “heavenly city of Jerusalem” were embellished with amethysts. “Hyacinthus” (probably aquamarine) was said to have magical powers as well, such as this prescription from a Middle English romance:

“if you find a hyacinthus engraved with a figure half woman and half fish

you are told to mount the stone in good gold. Put the ring on your finger,

cover the stone with wax, hold it tightly in your fist and you will be seen of

no man”

By around 1000 AD, semi-spherical stones called reading stones began to be used to magnify text, long before the invention of reading glasses.  Beryl (probably pale aquamarine) was one of the best stones for this purpose.

Amethyst and Aquamarine after the Renaissance

After the Renaissance, jewelry designs became more and more sophisticated, allowing the beautiful sea-green colors of aquamarine and purple of amethysts to be cut to maximally showcase the stones’ natural beauty.  New deposits of fine amethysts and aquamarines in Brazil opened-up the possibility of owning these gems to a wider swath of the population, and jewelers responded through ever greater creativity. Aquamarine earrings and amethyst earrings came into fashion, often incorporated into fanciful designs during the art nouveau period. Amethyst rings took unique forms, such as the mourning ring with compartments for mementos of the deceased.

One of the most striking qualities of amethyst and aquamarine jewelry in the 20th century through today is its diversity.  One of the most stunning collections of matching aquamarine jewelry is Queen Elizabeth II’s aquamarine parure, consisting of an aquamarine necklace with matching pendant earrings gifted to the Queen by the president of Brazil upon her coronation, and several matching pieces added later, including an aquamarine bracelet, brooch, and, perhaps most famously, a breathtaking aquamarine tiara.  

The Duchess of Windsor’s Amethyst Cartier Necklace

Among the most famous amethyst necklaces of all time is the Duchess of Windsor’s Cartier amethyst necklace, made in 1947, which features 30 amethysts. Royalty across Europe and beyond wearing amethyst tiaras and spectacular amethyst parures include Queen Sonja, Crown Princess Mette-Marit, and Princess Martha Louise of Norway,  Princess Marie of Denmark, Duchess of Cornwall Camilla, ladies of the grand ducal family of  Luxembourg, the Bavarian royal family, and members of the House of Bernadotte, the royal family of Sweden. 

Perhaps most modern of all is the growth of the phenomenon of using crystals as healing stones.  While there is no scientific evidence to support any physical healing effects from crystals, the psychological boost for people who believe that certain stones have power can be enough to heal illness via the placebo effect, and boost confidence to ensure success in stressful situations. 

For affordable, gem-quality aquamarine and amethyst jewelry, visit SuperJeweler’s collection of gems and settings. From the budget-conscious to the breathtaking, you’ll be sure to find the perfect amethyst or aquamarine for you or the one you love!

Dr. Copeland holds a PhD is in molecular and cellular biology, but she is also an avid history and geology enthusiast.  Normally a biomedical writer, she enjoys the chance to write about gemstones and the history and symbolism of jewelry.

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