Aquamarine: A Captivating Blue Gemstone

History

Aquamarine, named after the colour of seawater, has long been associated with the sea and sailors. It's said to have originated in the treasure chests of mermaids, and was believed to protect mariners and bring good health. This gemstone is also considered to enhance the happiness of marriages. Aquamarine is the modern birthstone for March and the gem for the 19th wedding anniversary. It's a popular choice for engagement rings, jewellery, and gemstone collections. The beautiful blue to blue-green hues of aquamarine evoke a refreshing dip in a cool pool.

Mineral Origins

Aquamarine is a variety of the mineral beryl, like emerald. Its blue to blue-green colour comes from iron in the crystal. Aquamarine is found in various locations around the world, with major deposits in Brazil, Tanzania, Kenya, Mozambique, Nigeria, and Madagascar. Other sources include Russia, Sri Lanka, Pakistan, and Afghanistan. Aquamarine is formed in granitic rocks, especially granite pegmatites. The crystals can grow to be quite large, with some reaching over a foot in length.

The Four C's

Colour

The most desirable aquamarines have a moderately strong, dark blue to slightly greenish-blue hue. Although some consumers prefer the natural sea-green colour, generally, a purer, more intense blue is more valuable. Aquamarine colours range from blueish green, blue-green, greenish blue to deep blue, and tones vary from very light to moderately dark. Heat treatment is often used to remove the yellow or green tints, leaving the stone with a more desirable blue colour.

Clarity

For faceted aquamarines, an eye-clean clarity grade is preferred (VS or VVS). Visible inclusions will lower the stone's value. However, some aquamarines have an icy quality due to their transparency which increases their value. Included stones, with effects that make the stone look like glacial ice, have also become popular in jewellery. It is now a trend to use included, but good-colour aquamarines as unique centrepieces for jewellery, or even as partially polished crystal slices or nuggets in necklaces. In some beryl crystals, there are enough parallel inclusions to allow cutters to fashion the rough to show a cat's-eye.

Carat

Aquamarines come in a wide range of sizes, from small to very large stones. Larger stones are more likely to exhibit a darker colour. Gems under 5 carats may not display desirable tones, therefore they are more often seen as featured stones rather than accents. The price per carat does not increase exponentially with size. In fact, it tends to drop for stones over 25 carats as they become too large for jewellery.

Cut

Aquamarines are often cut to enhance their colour and brilliance. Popular cuts include emerald cuts and Barion cuts, but aquamarines can be fashioned into almost any shape. The gem's hardness and transparency make it popular for artistic designer cuts and carvings. Gem cutters often use a 43° pavilion mains on aquamarine for the highest brilliance. Although low crown angles produce higher brilliance, higher crowns are used to deepen the colour.

Be Aware Of

Enhancements

Most aquamarines are heat-treated to remove green hues and make them bluer. This treatment is permanent and widely accepted in the jewellery industry and doesn't lower the value of the gem. The treatment does not affect tone, only the hue of the stone. It is undetectable with modern gemological equipment, so any pure blue aquamarine is usually considered to be heat-treated.

Simulants

Various materials can imitate aquamarine. Synthetic spinel, heat-treated zircon, and irradiated and heated topaz can be used as alternatives due to their blue colour. Always be aware of stones priced too cheaply for their apparent quality. A diamond tester or loupe exam can help distinguish between a topaz and aquamarine.

Synthetics

Synthetic aquamarines can be grown in labs and are difficult to distinguish from natural stones. These have essentially the same chemical, physical, and optical properties as natural aquamarines. Gemological labs can help determine if a stone is natural or synthetic.

Final Thoughts

Buying Tips

When buying an aquamarine, consider that the best stones are a marriage of colour and clarity, with a dark blue to slightly greenish-blue hue and no visible inclusions. Fine aquamarines are rare and expensive. Work with a jeweler who has expertise in aquamarines and can show you a variety of stones to compare. Trust your colour preferences, as a gem with more green may be beautiful and less costly than a pure blue one. Be aware that some aquamarines may be sold with trade names such as "Brazilian" or "Madagascar" which may refer to the colour rather than the gem's origin.

Jewellery Care

At 7.5 to 8 on the Mohs scale, aquamarines are durable enough for daily wear, but should be cleaned every three or four times they're worn. The safest method for at-home cleaning is warm water and gentle dish detergent, using a soft brush to scrub the stone and then air dry. Remove aquamarine jewellery before bedtime, as with other fine jewellery. Inclusions may not react well to mechanical cleaning techniques such as ultrasound or steam, increasing the risk of shattering. It is advised to consult with a gemmologist before using these methods.

Sources

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

Frequently asked questions

What does Santa Maria aquamarine mean?

Santa Maria is a trade name for a deep, intense blue aquamarine, originally from the Santa Maria mine in Brazil. Today it describes that top blue color rather than a guaranteed origin, and similar names like Santa Maria Africana are used. Treat such names as color descriptions and rely on a report for actual origin.

How is aquamarine different from blue topaz?

They look similar but are different minerals. Aquamarine is beryl colored by iron, and most natural-looking blues are lightly heated. Most blue topaz is colorless topaz turned blue by irradiation, and it is usually cheaper. A jeweler can separate them with simple optical tests, and a report settles it for a significant stone.

Why does aquamarine look cloudy?

Two causes. Natural aquamarine frequently contains fine hollow tubes and liquid inclusions that scatter light and give a milky appearance, which is common in larger crystals. The other cause is simply a worn or poorly finished polish, where surface abrasion from daily wear dulls the facets and can be corrected by repolishing.

What is the difference between natural and synthetic aquamarine?

Both share the same chemistry and look, but synthetic aquamarine is grown in a lab and can be hard to spot by eye. Natural stones formed in granite pegmatites over long periods. Because the visual difference is subtle, a gemological laboratory report is the dependable way to confirm a stone is natural.

How can I tell if aquamarine is real at home?

Aquamarine is noticeably light for its size, roughly 2.7 specific gravity against 3.5 or more for blue topaz, so a loose stone feels less dense than it looks. Natural material is usually a soft, slightly greenish blue and often carries fine parallel inclusions. A vivid saturated blue at a low price is almost always treated glass or synthetic spinel.

Is heat-treated aquamarine worth less than untreated?

No. Most aquamarine is gently heated to remove faint green or yellow tints and settle on a cleaner blue. The treatment is permanent, widely accepted, and undetectable, so it does not lower value. In practice almost any pure-blue aquamarine has been heated, and stones are priced on the beauty of the color, not the treatment.

What aquamarine color is most valuable?

A moderately strong, slightly greenish to pure blue in a medium tone is the most valued. Very pale stones are common and inexpensive, while deep, vivid blue is rarer and pricier. Some buyers love the natural sea-green tone, which can be beautiful and cost less than a pure blue of the same size.

Are included aquamarines worth anything?

They can be. While eye-clean stones command the highest prices, aquamarines with a frosty, icy look from fine inclusions have become a popular design choice, sometimes used as crystal slices or nuggets. Strongly colored included stones can make striking centerpieces. Inclusions that threaten durability, such as fractures, still reduce value.

Is aquamarine durable enough for an engagement ring?

Yes. Aquamarine is a beryl with a hardness of 7.5 to 8, hard and tough enough for everyday rings with reasonable care. Clean it with warm water, mild dish soap, and a soft brush. If a stone has visible inclusions, avoid ultrasonic and steam cleaners, which can stress those inclusions.

Does aquamarine fade in sunlight?

No. Aquamarine's blue comes from iron within the beryl structure and is stable to light, so normal wear and daylight will not weaken it. Prolonged high heat is a different matter and should be avoided, because heat is precisely what is used to modify the colour in the first place.

Can aquamarine go in an ultrasonic cleaner?

Only if the stone is free of visible fractures and liquid inclusions, which many aquamarines are not. Because those inclusions are so common in this species, warm soapy water and a soft brush are the sensible default. Avoid steam cleaning entirely, since heat can alter the colour.

Where is aquamarine found?

Brazil is the historic and still dominant source, with Minas Gerais producing the material behind the Santa Maria colour designation. Significant production also comes from Nigeria, Mozambique, Zambia, Madagascar, and Pakistan. In the United States, Colorado produces aquamarine and named it the state gemstone in 1971.

Which month is aquamarine the birthstone for?

March, with bloodstone as the traditional alternative. The pairing has held on the American list since 1912. Aquamarine's association with the month is generally read through the stone's water symbolism and the seasonal turn towards spring, which suits its pale sea blue.

What does aquamarine symbolise?

The name comes from the Latin aqua marina, meaning seawater, and the stone was carried by sailors as a talisman for safe passage and calm waters. That maritime association has carried into its modern reading as a stone of composure and clear communication.