Birthstone Guide: Aquamarine for those Born in March

The blue hues common to this beautiful stone are fitting considering the Latin aqua mare means ‘water of the sea’. Legends describe it as the mermaid’s stone, bringing luck to sailors and protecting them from the perils of the ocean. 

Beryl Gem-A Archive. Aquamarine birthstone
Facetted Beryl from the Gem-A Archive

A member of the beryl family, including emerald, heliodor, morganite and goshenite; aquamarine is distinguished by its blue to green colour. 

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Many aquamarines available in the gem market have been heat treated. Starting with a yellowish, greenish or bluish-green beryl, heat treatment leads to a stable blue colour. 

Where is Aquamarine Found?

Mainly found in mines in Africa and Brazil, the March birthstone can also be mined in Australia, China, Myanmar, Pakistan, Madagascar, Russia, USA and Sri Lanka. The trace amounts of iron found in aquamarine causes the sea like colour and is what distinguishes this stone from pure colourless beryl. 

Distinguishing Features of Aquamarines 

Aquamarine often occurs as a hexagonal-shaped long prismatic crystal, with striations and rectangular etch marks occasionally found on the prism surfaces. 

Beryl Aquamarine Crystal Rectangular Etch Pits on Prism Face. Image Courtesy of Pat Daly. Birthstone Aquamarine
Beryl Aquamarine Crystal Rectangular Etch Pits on Prism Face. Photo Credit Pat Daly.

The stone’s durability and bountiful supply make this stone a popular choice and it can be fashioned into most cuts, making it a firm favourite with many lapidaries. 

Read more: An Exclusive Interview with Gem Cutter John Dyer

Although many cut aquamarines are free of inclusions, two-phase inclusions (liquid and gas filled), spiky cavities and tubes parallel to the length of the crystal that look like rain are common.

Beryl Aquamarine Feather of Two Phase Inclusions. Image Courtesy of Pat Daly. Birthstone Aquamarine
Beryl Aquamarine Feather of Two Phase Inclusions. Photo Credit Pat Daly.

The Dom Pedro Aquamarine

Perhaps the most famous aquamarine specimen is the 10363 ct Dom Pedro, which weighs an astonishing 26 kg. To this day, it holds the honour of being the largest piece of aquamarine ever to be cut. It was specialists in Idar-Oberstein, Germany, who took on the challenge in 1992.

Discovered by three Brazilian miners in Pedra Azul, Minas Gerais in Brazil in the late 1980s, the original aquamarine was a meter-long. Accidentally dropped it fractured into three pieces and the Dom Pedro was the largest piece from the split. 

In 1991, Jürgen Henn from Idar-Oberstein, visited the owner of the large aquamarine crystal. However, the crystal was not for sale and he returned to Germany. In 1992 the stone went on the market and Jürgen asked his colleague Bernd Munsteiner to look at the stone. Bernd sent his son, Tom Munsteiner and Jürgen’s son Axel Henn, to strike a deal in Brazil and bring the stone to Germany. 

For a year Bernd worked on the stone, studying the crystal, drawing facet patterns, cutting, faceting and polishing. Before transforming the rough stone into the majestic obelisk, recognised and admired by many today. 

The Dom Pedro Aquamarine, from Brazil. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution. Birthstone Aquamarine
The Dom Pedro Aquamarine, from Brazil. Photo Credit Don Hurlbert. Image Courtesy of Smithsonian Institution.

The Dom Pedro first went on public display in 1993 at Basel, the annual gem fair in Switzerland. Almost cut up into smaller gemstones in the late 1990s, it was rescued by Jane Mitchell and generously donated to the Smithsonian, National Museum of History, Washington DC, USA. The awe-inspiring gemstone is in the permanent collection of the museum, housed in the National Gem Collection Gallery

Read more: An Interview with Dr Jeffrey Post of the Smithsonian Institution

Testing aquamarine

When viewed through a Chelsea colour filter aquamarine give a blue-green colour; different from the reaction of many of the other light blue gemstones. When tested with a dichroscope a blue/ green colour shows colourless and pale blue. The material is dichroic. ■

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Cover image beryl aquamarine crystal. Photo credit Pat Daly. 

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Understanding Dioptase

Did you think this might be emerald? You certainly wouldn't be the first to confuse the vibrant green of dioptase with the more recognisable, jewellery-lover's gemstone. Here, Gem-A assistant gemmology tutor, Dr Juliette Hibou FGA, explains more about the history, properties and origins of dioptase, an unusual collector's gem. 

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