March is a month of transition, marking the shift from the quiet stillness of winter to the vibrant bloom of spring. In the world of gemstones, it is represented by two stones—aquamarine and bloodstone—each with its own unique color, history, and symbolism. While bloodstone contributes a bold and earthy palette, the aquamarine is the more widely recognized of the two. Its color, a luminous and tranquil blue or blue-green, has captivated people for centuries. This article explores the color of the March birthstone, particularly focusing on aquamarine. We will uncover its geological origins, historical and cultural significance, gemological properties, and how its color is enhanced through treatment. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this article offers a comprehensive look at the color that defines one of the most cherished birthstones of the year.
The Blue of the Sea: Understanding Aquamarine's Color
Aquamarine, the birthstone of March, is a blue or blue-green variety of beryl, a mineral species that also includes emerald and morganite. Its name is derived from the Latin phrase aqua marina, which means "sea water," a reference to its color and the ancient belief in its connection to the ocean. The color of aquamarine is not just aesthetically pleasing—it carries deep symbolic meaning across cultures and eras. From calming the seas for sailors to symbolizing purity and serenity, aquamarine’s blue hue has long been a source of wonder and reverence.
The primary color of aquamarine is a clear, pale blue to deep blue-green, with the most desirable hues being those that closely resemble the color of the sky or the sea. This coloration is due to the presence of iron, specifically ferrous iron (Fe²⁺), within the crystal structure of the beryl mineral. The exact shade of blue can vary depending on the concentration and oxidation state of the iron, as well as the crystal's orientation and light exposure.
Interestingly, aquamarine is a pleochroic gem, meaning that its color can appear different depending on the direction from which it is viewed. This is a result of the gemstone's hexagonal crystal structure. When light enters the crystal at certain angles, it interacts differently with the iron atoms, causing subtle shifts in color perception. As a result, a single aquamarine gem can display multiple hues, from nearly colorless to vivid blue. This property is particularly important for gem cutters, who must orient the stone carefully to display the most desirable color when viewed from above.
In the gem trade, the most prized colors are those that display a pure, intense blue with minimal green undertones. Stones with a greenish cast are often considered less valuable, especially if the green is pronounced. However, aquamarine with a light blue-green color, sometimes referred to as "sea green", was particularly popular in the 19th century. Today, the most sought-after colors include "Santa Maria blue", a medium to dark blue with high saturation, and "sky blue", a light, clear blue that evokes the open sky.
Geological Formation and Sources of Aquamarine
Aquamarine is a variety of beryl, a mineral that forms in granitic pegmatite deposits, which are coarse-grained igneous rocks that develop from the slow cooling of magma. The formation of aquamarine requires specific geological conditions: the presence of iron, beryllium, and aluminum in the magma, along with a cooling environment that allows for the slow crystallization of the mineral. These conditions are relatively rare, which is why high-quality aquamarine is considered a semi-precious gemstone.
One of the most notable sources of aquamarine is Brazil, a country known for producing some of the largest and finest specimens. The Santa Maria de Itabira mine in Brazil is particularly famous for yielding aquamarine with the vivid blue known as "Santa Maria blue." This mine has produced some of the most iconic aquamarine gems in history, including the Dom Pedro Aquamarine, a 10,363-carat gem displayed at the Smithsonian Institution. The Dom Pedro is considered the largest faceted aquamarine in the world, a testament to the rich deposits of this gemstone in Brazil.
Other notable sources include Siberia, where aquamarine was historically mined, and Madagascar, which has become a significant producer in recent decades. Aquamarine can also be found in Nigeria, Afghanistan, and the United States, particularly in Colorado and California. However, the most highly regarded stones—those with the clearest color and highest clarity—typically come from Brazil and Siberia.
The formation of aquamarine often includes inclusions that can affect the stone’s appearance. These inclusions, sometimes referred to as "needle-like" or "feathery" inclusions, are characteristic of beryl and can add to the stone's charm. However, inclusions that are too prominent can reduce the stone's clarity and value. Aquamarine is generally free from inclusions, especially when compared to other gemstones of similar hardness, making it a desirable choice for fine jewelry.
Enhancing the Color: Heat Treatment of Aquamarine
One of the most common methods for enhancing aquamarine is heat treatment, a process that has been used for centuries to improve the color of the gemstone. Aquamarine often contains iron impurities that can result in green, yellow, or brown color components alongside the blue. Heating the stone to temperatures between 400 and 600°C can convert some of these impurities into a more desirable blue hue. This process removes the unwanted color components and enhances the natural blue of the gem.
Heat treatment is both safe and permanent, making it a widely accepted practice in the gemstone industry. It is especially important for aquamarine because the stone's color can vary significantly depending on the presence of these impurities. After treatment, the aquamarine displays a brighter, more saturated blue, which is highly valued in the market. In fact, most aquamarine on the market today has undergone some form of heat treatment.
The effects of heat treatment can vary depending on the original color of the stone. Stones that are naturally blue may not require much heating, while those with a strong green or yellow cast may need more extensive treatment to achieve a desirable blue. The treated aquamarine does not lose its color over time, and it is considered stable under normal wear conditions.
In addition to enhancing color, heat treatment can also improve the clarity of the stone. Some inclusions that are visible in their natural state may become less noticeable after heating, further increasing the stone's value. However, it is important to note that heat treatment does not alter the hardness or toughness of the gem. Aquamarine remains a relatively tough gemstone, with a Mohs hardness of 7.5 to 8, making it suitable for everyday wear.
Historical and Cultural Significance of Aquamarine
Aquamarine has a rich historical and cultural significance, particularly in its association with the sea and its protective properties. Ancient civilizations, including the Greeks and Romans, believed that aquamarine had the power to calm the seas and protect sailors from the dangers of the ocean. Sailors would carry aquamarine with them on long voyages, believing it would help them avoid shipwrecks and ensure safe passage. The gemstone was also thought to ward off enemies and bring intellectual clarity, making it a popular stone among warriors and scholars alike.
One of the most fascinating legends surrounding aquamarine is the belief that it was created by the sea god Poseidon. According to this myth, aquamarine was formed when seawater was transformed into crystal, giving the stone its deep blue color. Another legend suggests that mermaids' tails are made of aquamarine, adding a touch of magic to the gem. These stories reflect the deep connection between aquamarine and the ocean, a theme that has persisted throughout history.
In addition to its association with the sea, aquamarine has also been linked to marriage and love. In some cultures, it was believed that aquamarine could bring happiness and harmony to marriages, making it a popular gift for couples. The gemstone was also thought to soothe the emotions, helping to calm anxiety and promote inner peace. These beliefs contributed to aquamarine's popularity in jewelry and amulets, particularly during the 19th and early 20th centuries.
Today, aquamarine is still considered a stone of protection and tranquility, and it is often used in spiritual practices and holistic healing. Some believe that aquamarine can enhance communication and emotional stability, making it a valuable tool for those seeking balance and clarity in their lives.
Aquamarine as a Modern Birthstone
Aquamarine became the modern birthstone for March in the 19th century, although it had been known and valued for centuries before that. The adoption of birthstones as we know them today began in the 1800s, when jewelers in Germany and Poland started selling jewelry that featured the gemstones associated with each month. This practice was further popularized by the Tiffany & Co. birthstone poems published in 1870, which are often attributed to an anonymous Gregorian author.
Before aquamarine became the official March birthstone, bloodstone was the only gemstone associated with the month. Bloodstone, a green chalcedony with red spots of iron oxide, is a stark contrast to the blue of aquamarine. While bloodstone is still recognized as a traditional March birthstone, aquamarine has become the more widely accepted and popular choice.
Aquamarine's popularity as a birthstone is due in part to its versatility and beauty. It is a durable gemstone with a high luster, making it ideal for use in a variety of jewelry pieces. Its light blue color complements a wide range of skin tones and settings, and it can be easily paired with other gemstones or used as a center stone in a piece of jewelry.
In addition to its aesthetic appeal, aquamarine is also associated with positive symbolism, such as protection, tranquility, and purity. These qualities make it a meaningful choice for those born in March, and it is often given as a gift to commemorate birthdays, anniversaries, and other special occasions.
Care and Cleaning of Aquamarine Jewelry
Despite its hardness and durability, aquamarine requires careful handling to maintain its beauty and longevity. With a Mohs hardness of 7.5 to 8, aquamarine is relatively tough, but it is not as hard as diamond or sapphire, and it can still be damaged by hard knocks or exposure to harsh chemicals.
One of the most important aspects of aquamarine care is avoiding exposure to strong acids or solvents, which can damage the surface of the gem. It is also important to store aquamarine jewelry separately from other gemstones, as harder stones like diamond or topaz can scratch the aquamarine if they come into contact with it.
Cleaning aquamarine is relatively simple, but it should be done with care. While aquamarine can be cleaned at home, it is always best to seek professional cleaning for valuable or antique pieces. At home, aquamarine can be cleaned with warm, soapy water and a soft brush. A mild detergent, such as dish soap, can be used to remove dirt and oils that accumulate on the surface of the gem. After cleaning, the stone should be rinsed thoroughly with warm water and dried with a soft cloth.
It is important to avoid using ultrasonic cleaners for aquamarine, as they can damage the inclusions or weaken the setting. Steam cleaners should also be avoided, as the high heat can alter the color or clarity of the gemstone. If you are unsure about how to clean your aquamarine jewelry, it is best to consult a professional jeweler who can provide safe and effective cleaning methods.
Conclusion
Aquamarine, the blue gemstone of March, is a remarkable stone that has captivated people for centuries. Its color, a clear and tranquil blue or blue-green, is one of its most defining characteristics. This color is caused by the presence of iron in the beryl mineral, and it can vary from light sky blue to deep ocean blue. The most desirable colors are those with a pure, intense blue with minimal green undertones, and these are often enhanced through heat treatment.
Aquamarine is formed in granitic pegmatites, and it is found in Brazil, Siberia, Madagascar, and other parts of the world. It is a pleochroic gem, meaning that its color can appear different depending on the direction from which it is viewed. This property is important for gem cutters, who must orient the stone carefully to display the most desirable color when viewed from above.
Historically, aquamarine has been associated with the sea, and it was believed to calm the waves and protect sailors from danger. It was also thought to bring happiness to marriages and promote intellectual clarity. These beliefs contributed to its popularity in jewelry and amulets, and they continue to influence its modern significance as a birthstone.
Aquamarine is a versatile and beautiful gemstone that is ideal for a variety of jewelry pieces. Its hardness and durability make it suitable for everyday wear, and its calming blue color adds a touch of serenity and elegance to any piece. With proper care and cleaning, aquamarine jewelry can be worn and cherished for a lifetime.
Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, aquamarine offers a rich and fascinating study of color, history, and symbolism. Its blue hue, reminiscent of the sea and the sky, continues to inspire and captivate, making it a true treasure of the March birthstone.