Aquamarine, a variant of the mineral beryl, is a captivating gemstone, both for its lovely sky-blue to sea-green hues and for its striking physical characteristics.
Named after the Latin words for 'water' and 'sea', aquamarine enchants with colours that range from near colourless to deep blue or blue-green. The most sought after shade is a rich medium blue.
Aquamarine's appeal isn't limited to its beautiful blue colours. Its elongate hexagonal crystals, often etched with fascinating surface patterns, are also a sight to behold. Aquamarine crystals may be striated along their length, and their terminations can be flat or bevelled, sometimes tapering to an end. The charm of this gemstone lies in its ability to form large, flawless crystals, making it possible to fashion sizable and striking pieces of jewellery. Despite its splendour, aquamarine is not incredibly rare, making it a great choice for jewelry enthusiasts and collectors alike.
Aquamarine is primarily known by its Latin-derived name. Occasionally, it may be confused with other similarly coloured gemstones like blue topaz and zircon, but the distinctive properties of aquamarine set it apart.
From near colourless to deep blue or blue-green, aquamarine is a beautiful gemstone. A unique property of this gemstone is its strong dichroism, meaning it can show different colours when viewed from various angles. The colours seen in aquamarine are caused by impurities of iron absorbed into its crystal structure during its formation.
Brazil has been the leading producer of aquamarine since the 1800s, particularly the Minas Gerais state which is known for its pegmatite and gem gravel deposits. Another significant source of aquamarine is Pakistan. Other notable regions include Madagascar, Afghanistan, Kenya, Zambia, Nigeria, Mozambique, Namibia, Russia, the USA, Uruguay, India, Sri Lanka, Myanmar, China and Australia.
Aquamarine is one of the birthstones of March. It shares this honour with another gem, bloodstone, which is quite different with its dark green colour and distinctive red specks.
The world of aquamarine is brimming with interesting tales and fascinating facts. One of the most notable instances is the discovery of the Dom Pedro, the largest known cut aquamarine, carved into an obelisk nearly 35 cm tall, weighing a staggering 10,363 ct. This remarkable piece now resides in the Smithsonian Institution in Washington, DC, USA.
Another intriguing feature of aquamarine is its strong pleochroism, enabling it to exhibit different colours when viewed from different angles.
Aquamarine, while not incredibly rare, varies in value based on several factors. The most desirable pieces are those exhibiting a saturated medium blue to slightly greenish-blue colour. Also, the clarity of the stone is a significant factor in determining its value, with clear, inclusion-free stones being the most valued.
When considering the quality of an aquamarine gemstone, several factors come into play. The colour, clarity, and cut of the gemstone are all significant quality determinants. A high-quality aquamarine is medium blue to slightly greenish-blue, has good clarity with minimal inclusions, and is cut in a way that maximises its colour and brilliance.
Aquamarine is often heat-treated to enhance its blue colour by removing any green overtones. This treatment is undetectable and produces a stable blue colour. However, it's important to note that this does not significantly affect the value of the gemstone.
Rarely, surface-reaching fractures are filled to improve the gemstone's appearance.
Synthetic aquamarine does exist, but it's not often seen in the market. Imitations of aquamarine include pale blue glass and synthetic spinel, which do not exhibit the pleochroism characteristic of genuine aquamarine. Tools like the Gem-A Chelsea Colour Filter can help distinguish real aquamarine from its imitations.
Cleaning aquamarine can be done safely using ultrasonic or steam cleaners unless the gemstone contains fluid inclusions or fractures. While this gemstone is quite hard and durable, it is also brittle and vulnerable to knocks.
Aquamarine has a rich history, with notable pieces like the Dom Pedro. The Natural History Museum in London also holds a near flawless 898.7 ct faceted aquamarine gemstone, another testimony to the awe-inspiring size that these crystals can reach.
Aquamarine can be confused with similarly coloured gemstones like blue topaz and zircon. However, aquamarine's lower refractive index and dichroism can help distinguish it from these gemstones.
As a type of beryl, aquamarine is related to several other gemstones, including emerald, another variant of beryl. Although these gemstones share a similar composition, their different impurities and colours set them apart. Emerald, for example, gets its green colour from chromium and vanadium impurities, while aquamarine's blue tones come from iron impurities.