Aquamarineis the birthstone of the month of March. Aquamarine crystals can reach significant dimensions, up to several kilos. Due to pale blue colours, aquamarines found in jewellery are relatively large in size in order to showcase their colour. They do not show any inclusions to the naked eye.
After emerald, aquamarine is the most popular variety of beryl -- and by the late Queen Elizabeth II of England, her favourite! Aquamarine is a symbol of fidelity between spouses and is believed to guarantee a happy marriage.
Characteristics of the March Birthstone
The color of aquamarine varies from light blue to deeper blue to light blue-green. Generally, in shades of pale blue, these stones increase in value when the colour is more pronounced.
In nature, blue-green is mostly found, however by heat treatment, the shade of yellow is removed leaving only a blue aquamarine. This treatment is stable, and performed on majority of stones.
Gem quality aquamarines are transparent, with no visible inclusions, and a vitreous lustre. In rare cases, it may showcase chatoyancy (cat’s eye effect).
Although aquamarines used in jewellery are generally free of inclusions, when they are present, you may find crystals, two-phases (liquid and gas/crystal), or thin parallel tubes either hollow or liquid filled which look like rain.
Synthetic aquamarine exists, but there is rarely found on the market. The hydrothermal method can be recognized by irregular growth lines. Blue synthetic spinel (Verneuil method) is the best imitation of aquamarine and is very common.
Fabricated glass and synthetic spinel are common imitations. Glass is usually recognizable by the presence of bubbles and its different properties.
Blue synthetic spinel (Verneuil method) is the best imitation of aquamarine and is very common.
Where is Aquamarine found?
The main producing country is Brazil, followed by Madagascar which produces the most beautiful blue.
Aquamarines from Nigeria and Namibia are increasingly found in the market, while Russia and Ukraine produce aquamarine that is often shipped to Brazil where it is processed, cut and marketed.
The main confusion with natural stones is untreated natural blue topaz. When they come in shades of pale blue, it is almost impossible to tell an aquamarine from a topaz of the same tone. To do this, gemmological instruments are necessary. An aquamarine can also be mistaken for a pale blue zircon; the high dispersion of zircon should give a first clue in identification.
The hardness of aquamarine is 7 ½ to 8 and it has no cleavage. Although part of the same family as emerald, also with a hardness of 7.5 to 8, aquamarine does not have the cracks of emerald and is much less fragile.
Caring Tips for Aquamarine
For the bench jeweller, aquamarine is sensitive to heat. Immerse the stone in wet water or sand or cover it if repairs are required. Aquamarine is susceptible to thermal shock.
Cleaning methods that are completely safe are ultrasound and warm soapy water. Steam cleaning is to be avoided.