Aquamarine

Introduction

Aquamarine, a mesmerizing gemstone with hues that reflect the serene blues of the ocean, is a member of the beryl family, which also includes emerald. Renowned for its exceptional clarity and captivating color, aquamarine has been a symbol of youth, hope, and eternal happiness for centuries. Its name is derived from the Latin "aqua" meaning water and "marina" meaning sea, which aptly describes its tranquil appearance. Historically, aquamarine has been revered not only for its beauty but also for its perceived protective qualities, especially among sailors who believed it could calm the sea and safeguard against dangers. Beyond its nautical connections, aquamarine is also associated with communication, courage, and compassion, making it a gemstone rich in both aesthetic and symbolic value.

Color and Varieties

Aquamarine's color spectrum ranges from pale, almost translucent blue to vivid deep sea blue and blue-green. The color is determined by the amount of iron within the beryl structure, with more iron leading to deeper blue hues. Some aquamarines exhibit a natural greenish tint, but these stones are often heat-treated to remove the green and enhance the blue, which is considered more desirable. The most sought-after aquamarines are those that display a pure, deep blue color, reminiscent of the clear ocean on a sunny day. The color is typically uniform throughout the stone, though some may exhibit slight color zoning. While blue aquamarines are the most famous, the gemstone can also be found in greenish-blue and even yellowish hues, though these are less common and less valued in the market. The best quality aquamarines are known for their exceptional clarity, often being free of inclusions visible to the naked eye, which contributes to their brilliance and luster.

Formation and Occurrence

Aquamarine forms in the hexagonal crystal system, typically within granite pegmatites, which are igneous rocks known for hosting large, well-formed crystals. The gemstone is primarily found in regions with rich geological history, where tectonic activity has created the conditions necessary for its formation. Brazil is by far the largest producer of aquamarine, particularly in the states of Minas Gerais, where some of the most beautiful specimens have been unearthed. Other notable sources include Pakistan, particularly in the Shigar Valley, which produces aquamarines with a distinctive deep blue color, and Madagascar, known for its high-clarity stones. In the United States, aquamarine can be found in Colorado, particularly on Mount Antero, where it is often extracted from high-altitude deposits. Aquamarine crystals are typically found in association with other minerals such as quartz, feldspar, and mica, and can form large, well-formed crystals, sometimes reaching several feet in length. These crystals are often embedded within the host rock and must be carefully extracted to avoid damage.

Historical and Cultural Significance

Aquamarine has been cherished throughout history, with roots tracing back to ancient civilizations. The Romans believed that aquamarine was sacred to Neptune, the god of the sea, and would protect sailors on treacherous voyages. They also believed that the stone had the power to heal ailments of the heart and liver and to help ensure good health and a long life. In medieval times, aquamarine was considered an antidote to poison and was also thought to act as an oracle crystal, providing insight and foresight to those who gazed into its depths. The gemstone has also been associated with the calming of anger and the rekindling of love. In more recent history, aquamarine has been a favorite among royalty and the elite. One of the most famous aquamarine pieces is the aquamarine tiara, a gift from the President of Brazil to Queen Elizabeth II in 1953. The gem has also found its place in the metaphysical community, where it is believed to enhance communication and courage and to bring peace and clarity to those who wear it.

Identification and Grading

Identifying aquamarine involves examining several key characteristics, including color, clarity, cut, and carat weight. The most valuable aquamarines exhibit a rich, deep blue color with no green or yellow undertones. Clarity is another critical factor, with high-quality stones being free of visible inclusions. However, some inclusions, such as liquid-filled tubes, are common in aquamarine and can help to authenticate the stone. The stone’s refractive index, which measures how light bends as it passes through the gem, is also a vital diagnostic tool, with aquamarine typically showing a refractive index between 1.577 and 1.583. Birefringence, which causes a double image when looking through the stone, is another test used by gemologists to identify aquamarine. Cut also plays a significant role in the gemstone's overall appeal. Aquamarine is often faceted to maximize its brilliance and color, with emerald cuts, round cuts, and ovals being the most popular shapes. Larger stones, particularly those over 10 carats, can command a premium, especially if they are of exceptional color and clarity.

Treatments and Enhancements

To improve their color, many aquamarines undergo heat treatment. This process, typically performed at temperatures between 400 and 450 degrees Celsius, can enhance the blue color by removing any yellow or green tones that might be present. Heat treatment is a common and accepted practice in the gemstone industry, and it is generally stable, meaning that the enhanced color will not fade over time. However, the treatment should be disclosed to buyers, as untreated stones, especially those with a natural deep blue color, can be more valuable. In some cases, aquamarine may also be irradiated to improve its color, though this practice is less common. Despite these treatments, aquamarine remains a durable gemstone, and its beauty and brilliance are long-lasting, making it a favored choice for both casual and fine jewelry.

Cutting and Polishing

Cutting and polishing aquamarine require great skill and precision to maximize the stone's natural beauty. The gemstone’s hexagonal crystal structure allows for a variety of cuts, but emerald cuts and oval shapes are particularly popular due to their ability to enhance the stone's clarity and color. The emerald cut, with its long facets and step-like appearance, is especially effective at showcasing the stone's color, while round and oval cuts can add brilliance and sparkle. When cutting aquamarine, lapidaries must consider the orientation of the crystal to avoid areas of potential weakness and to maximize the depth of color. Polishing is equally important, as aquamarine’s vitreous luster can be brought to a high shine with the right techniques. The result is a gemstone that not only looks stunning but also feels smooth and luxurious to the touch. High-quality aquamarine is often set in precious metals such as gold or platinum, with the simplicity of the setting allowing the stone to take center stage.

Uses

Aquamarine's combination of beauty, durability, and symbolic significance makes it a versatile gemstone in the jewelry world. It is commonly used in rings, necklaces, earrings, bracelets, and even tiaras. Because of its association with the sea and the sky, aquamarine is often favored in nautical-themed jewelry, making it a popular choice for sailors and those with a deep love for the ocean. Its durability, with a hardness of 7.5 to 8 on the Mohs scale, ensures that it can withstand everyday wear, making it a practical choice for engagement rings and other pieces of jewelry that are worn daily. In addition to its use in fine jewelry, aquamarine is also prized by collectors and crystal enthusiasts, who value it for its beauty as well as its purported metaphysical properties. Whether set in a simple band or a more elaborate design, aquamarine’s timeless appeal makes it a gemstone that continues to captivate people around the world.

Famous Specimens

Among the most famous aquamarine specimens is the Dom Pedro, an extraordinary 10,363-carat aquamarine obelisk named after Brazil's first two emperors, Pedro I and Pedro II. The Dom Pedro is the largest faceted aquamarine in the world and is currently housed in the Smithsonian Institution's National Museum of Natural History in Washington, D.C. Another notable aquamarine is the Martha Rocha, a 1.69 kg stone found in Brazil in 1954 and named after a famous Brazilian beauty queen. The Martha Rocha aquamarine was once considered the largest and finest in the world, and it remains a symbol of the richness of Brazilian gem deposits. Aquamarine has also made its mark in the world of fine jewelry, with several pieces featuring the gemstone in the British royal collection. The most famous of these is the aquamarine tiara, a gift to Queen Elizabeth II from the Brazilian government, which features a large central aquamarine flanked by smaller stones, all set in a platinum band.

Market and Value

Aquamarine’s value is determined by several factors, including color, clarity, size, and origin. The most valuable stones exhibit a rich, deep blue color without any green or yellow undertones. Clarity is also crucial, with clean, transparent stones commanding higher prices. Larger stones are rare and therefore more valuable, particularly those over 10 carats with exceptional color and clarity. Aquamarine from certain locations, such as Santa Maria de Itabira in Brazil, where the stones are known for their intense color, can also fetch higher prices. While aquamarine is more affordable than some other gemstones, it remains a popular and sought-after stone, with prices ranging from a few hundred to several thousand dollars per carat, depending on quality. The gemstone’s widespread availability and its association with March as a birthstone also contribute to its strong demand in the market.

Care and Maintenance

Aquamarine is a durable gemstone, but it still requires proper care to maintain its beauty. It should be stored separately from other gemstones to prevent scratching, as it can be damaged by harder stones such as diamonds. Cleaning aquamarine is relatively straightforward; warm soapy water and a soft brush are generally all that is needed. Ultrasonic cleaners are usually safe for aquamarine, but steam cleaning should be avoided, as the stone’s inclusions can be sensitive to heat. It is also important to protect aquamarine from prolonged exposure to direct sunlight, as this can cause the color to fade over time. When wearing aquamarine jewelry, it’s best to avoid harsh chemicals, such as bleach or chlorine, which can damage the stone or its setting. With proper care, aquamarine can remain as stunning and brilliant as the day it was first cut and polished.

Synthetic and Imitation

While natural aquamarine is widely available, synthetic versions do exist, although they are relatively rare. These lab-created stones are produced using hydrothermal or flux growth processes, which replicate the natural conditions under which aquamarine forms. Synthetic aquamarines have the same physical and chemical properties as their natural counterparts, but they can often be identified by the absence of natural inclusions and by their lower price. More common than synthetics are imitation aquamarines, which are often made from blue glass or other less expensive gemstones, such as blue topaz or synthetic spinel. These imitations can be convincing to the untrained eye but can usually be identified by a gemologist using standard gemological tests, such as refractive index and birefringence. When purchasing aquamarine, it is important to ask for certification from a reputable gemological laboratory to ensure the stone's authenticity.

Environmental and Ethical Concerns

The mining of aquamarine, like many gemstones, can have significant environmental and social impacts. In some regions, gemstone mining has led to deforestation, soil erosion, and water pollution, all of which can have devastating effects on local ecosystems and communities. Additionally, there are concerns about the working conditions of miners, particularly in developing countries, where labor rights may not be strictly enforced. To address these issues, some jewelry companies are increasingly focusing on sourcing aquamarine from mines that adhere to environmentally responsible practices and that treat their workers fairly. Initiatives such as the Responsible Jewellery Council and Fairtrade Gold are helping to promote ethical sourcing practices within the industry. Consumers are also encouraged to ask about the origins of their gemstones and to choose pieces that have been sourced ethically and sustainably.