The Beryl family includes morganite and heliodor; however, it is famous for two gemstones in particular: emeralds and aquamarines.
Whereas an emerald is a green gemstone with blue undertones, its sister aquamarine is blue with green undertones. As the name suggests, the colour of aquamarine is reminiscent of the sea, with hues ranging from light blue to green-blue to deep blue.
While not as famous as emerald, aquamarine has a few qualities that secure its place as one of the world’s most precious gemstones, namely, size and clarity.
Unlike emeralds, which become notoriously fractured during formation making cutting and fashioning more fraught, aquamarine forms in large crystals which are often void of visible inclusions.
The most sought-after colour has been dubbed ‘Santa Maria’, a saturated deep blue originally found in gemstones from the Santa Maria mine in Brazil.
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THE FACTS |
| Family: | Beryl |
| Hardness: | 7.5 - 8 |
| Toughness: | Brittle |
| Colour: | Pale blue to greenish blue to rich blue |
| Cause of colour: | Ferrous Iron (Fe2+) |
| Main sources: | Brazil, Madagascar, India, Pakistan, Namibia, Mozambique |
| Acceptable treatment: | Heat |
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With the supply from that mine mostly exhausted and the rich blue colour now being found in other areas across the globe, the term ‘Santa Maria’ has been expanded to include gemstones that meet strict colour grading criteria.
With that said, it is often inappropriately applied, and it pays for jewellers to be wary of any gemstone described as a ‘Santa Maria aquamarine’ and to undertake further investigation before paying a premium price.
Most aquamarines are a paler blue and this is why we will often see aquamarines cut in larger sizes, with Brazilian gemstones needing to be at least 10 carats to attain the best depth of colour.
This might also explain why some of the world's most famous aquamarines are not found in jewellery but are incredibly large gemstones. The largest is the Dom Pedro aquamarine tower, which is 35cm in length and weighs an enormous 10,363 carats.
Remarkably, the original rough crystal was even larger but broke during removal from the Minas Gerais mine.
Historically, Brazil has been the most important source of aquamarines. Indeed, the blue stone is so synonymous with the South American country that it became a favourite of Brazilian presidents to gift foreign dignitaries.
This includes the Roosevelt Aquamarine, an impressive 1,300-carat faceted gemstone gifted to Eleanor Roosevelt, the then-First Lady of the United States, in 1947.
Despite its luxury status, it is interesting to note that aquamarines are not gemstones likely to be made synthetically. Instead, it is more common in the market to see an imitant masquerading as an aquamarine, such as synthetic blue spinel or blue topaz.
Other imitant gemstones to watch out for are blue tourmaline, blue zircon, and blue apatite.
To the consumer, the question can be: Why should they pay more for an aquamarine when they can get a similar colour in blue topaz as an inexpensive alternative?
To answer that question, it is worth educating yourself on the difference between the colouring of the two gemstones.
To achieve a blue colour in topaz, the gemstone must undergo treatment in a nuclear reactor before being stored for a period to reduce radioactivity to acceptable levels.
Supply is plentiful, and it is a popular choice for affordable jewellery.
By contrast, aquamarine is a much rarer gemstone and is naturally blue. Most gemstones only undergo moderate and permanent heat treatment to intensify the shade of blue and remove any green or yellow undertones.
As always, a natural gemstone with minimal intervention will be greatly valued in comparison with a synthetic or highly treated alternative.
Aquamarine is associated with fine jewellery and has a long and prestigious history. It enjoys a revered place on the market and is sure to fascinate for many years to come.
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