Martin Rees, Jeweller and Pawnbroker

Beryl Gemstones - Emerald and Aquamarine

Emerald showing inclusions

A typical emerald, with many inclusions and fractures.  I have seen much worse; clear stones are rare and valuable.

Under the microscope emeralds are wonderful.  Each fracture is a pleasure, and many of the inclusions are crystals, beautiful in their own right.  I can easily spend half an hour just admiring one stone!
Beryl in its pure form is colourless, however various 'impurities' within the crystals give it various colours - emerald green is the best known.  Beryl forms in granite and crystals (not gem quality) can weigh up to a ton!  Its chemical composition is aluminium beryllium silicate.
Why are emeralds normally fractured, while most aquamarines are clear?  The answer probably lies in the impurites which give emerald its beautiful colour.  They also make the stone brittle, thus increasing the chance it will fracture while forming in the earth.
I have only mentioned the most common Beryl gems here.  Others include Yellow Beryl and Morganite, which varies between pink, orange and purple.

Treatments before purchase

Assume emeralds have been fracture filled unless guaranteed untreated.  This filling may be lost eventually, but stones can be re-treated.  Emeralds are occasionally dyed to improve the colour.
Aquamarine is easily available unflawed, so fracture filling is not needed.  However most stones are naturally a green blue, and are heat-treated to remove the green tint.  The treatment is permanent


Beryl stones are easy to clean, but very hot liquids are unwise.  Always remember that, although hard, these stone - like other gemstones - are somewhat brittle and can be damaged by a severe blow.
Emeralds normally have inclusions, flaws and fracture fillings;  so they should not be soaked when cleaning.  A good emerald is valuable, we would recommend taking it to a jeweller once a year to check its mount is secure, and the jeweller can clean it at the same time.


These are the bright green form of beryl and may have been used in jewellery as early as 3500BC.  However the early emeralds were from Egypt and were badly flawed.  It was only after 1500AD that better quality stones were found in South America.
Emeralds were the jewels of Venus, Goddess of Love.  They were thought to bring success in love.  They were also linked to Diana, guardian of women and young girls.  The Ancient Egyptians believed emeralds could heal eye diseases.  They are the May birthstone.


Aquamarine means 'Water of the Sea,' and the stone is a pale blue-green colour.  As remarked earlier, aquamarine is often found totally unflawed. It is a beautiful, light-coloured stone.
In ancient times it was used as a protection against drowning and sea-sickness, and was thought to bring good luck to fishermen.   It is the March birthstone.

Most aquamarine have few if any inclusions.  We were rather fortunate that in December 2006 a friend in the trade lent us quite a few stones.  He wanted us to confirm their identity, and while most were clear, we found these fascinating flaws.
The stones look light blue under normal light. They appear dark here, because I used a fibre-optic lamp to better show the inclusions.

Aquamarine with a 'rainfall' of growth tubes

This stone shows a 'rainfall' of growth tubes.  These tubes are part of the complex crystal structure of Beryl.  Some are so thin that an interference effect makes them look coloured.  This happens when the thickness of the inclusion is similar to the wavelength of light - just like an oil film on a wet road. Click here for larger image, 177Kb (will open in new tab).

Aquamarine with fluid inclusions

Most of the time this stone looks clear, but when the light catches it at just the right angle, these beautiful interference colours appear.  They are caused by thin fluid inclusions along a flaw.  Click here for larger image, 73KB (opens in new tab).

Emerald with range of inclusions

An emerald with a complex range of inclusions.  The brown crystals are probably pyrite, while the large crystal near the top may be felspar, and the small black inclusions are probably magnetite.  The only way to be certain would be to cut open the stone (thus destroying it) for chemical analysis. Click here for larger image, 245KB (opens in new tab).