Gemólogos.

                       C.C.C.T Tamanaco, Pirámide Invertida, Piso 3, oficina 323-A Chuao- Caracas, Venezuela.

TelFax: 0212-959.39.95 Cel. 0416-6325802

www.escueladegemologiaamericana.com   E-mail: auragod@cantv.net

THE AQUAMARINE. I
By Aura Godoy.

               

With its placid, blue sky color, free of any turmoil, or with the coloring of our shallow, warm seas, the glossiness of its sheen and the clearness of its crystals, it all imparts to the aquamarine a quiet and simple beauty which has captivated man from early times.

This is another variety of the extensive family of beryls, and is, after the emerald, the most esteemed of them.

Its name originated from a Latin word which meant “Sea water”.

It has been a companion to man since days of yore and became the favorite of lover, a talisman of happy marriages, a symbol of appreciation and fidelity; it was considered to have powers to ward off the forces of evil and certain therapeutical values, and was used to cure some maladies of the eyes.

The aquamarine is beryl and aluminum silicate ((SiO3)6Be3Al2), and its handsome color comes from the presence of light traces ferrous oxide. It crystallizes in the hexagonal system; its hardness is 7.5 on the Mohs scale.

It is found with large sized crystals, generally free of inclusions, and stones have had weights of more 100 kilo.

The most common inclusions of this gem are: liquid feathers that have a certain likeness to the flowerings of the chrysanthemum, transparent or dark capillary tubes, full of metallic oxides (iron) or of liquids, and negative crystals and liquid inclusions in the form of finger prints.

The color of the aquamarine goes from blue or greenish light blue to bluish green. The most common color is greenish blue. The gem’s tone also varies from very pale (a very delicate tint) all the way to pronounced full colors.

These days, so as to improve the color and eliminate the greenish tinge, the great majority of these gems are given a thermo treatment.

The most common cut is the emerald shaped style, with some variations. Because the coloring of the aquamarine goes in different and opposite directions (this is the dichroism phenomenon), the cutter has to use his expertise and ability to highlight the blue color in the crow, and relegate the green hue towards the pavilion of the gem.

 

Continue the next article.

THE AQUAMARINE. II

By Aura Godoy.


To identify the aquamarine, like any other precious stone requires the services of a gemologist, generally it is done by appraising its physical and optical properties. The gem that it most looks like is “apparently” the blue topaz, however, the refraction index and specific weight of each of them is completely different.
The refraction index of the aquamarine is 1.577 – 1.583, and of the blue topaz it is 1.629 – 1637. The difference becomes more evident when each gem is weighted, if they are loose. If both were of the same size, the variation in weight could be of the order of 30%, because of the difference in their specific weight.
The aquamarine has a specific weight of 2.68 and the blue topaz 3.52.
Another stone somewhat similar in color to the aquamarine is the synthetic spinel, which can be distinguished likewise by analyzing its physical and optical properties.
The most important deposits are: those in Brazil (Minas Geraes) which are of the alluvial type and are also found in pegmatite, the color being a greenish blue, although some very beautiful specimens can be obtained, in Madagascar they appear in pegmatite and intense color of the gems, in Russia they are found in the Ural Mountains, While Ceylon produces gems with beautiful hues.
Famous aquamarines: none have been given names, but many beautiful crystals of colossal size have been found, amongst the largest stones is an aquamarine extracted in Brazil in 1920 with a weight estimated at 110 carats, very transparent an with a handsome blue tinge, which was sold for $25.000 and was cut into various gems, all of optimum quality. The Smithsonian Museum of Natural History has a part of the external portion of this fabulous gem, which weighs almost 6 kilos, and is still in the rough.
The British Science Museum has an aquamarine on exhibit that is cut in a rectangular form, in other words like an emerald, with a weight of 879.50 carats, of a sea green color, and completely pure.
The Smithsonian Museum of Natural History also possesses other aquamarines of optimum quality, amongst which there is one 271 carat and of Russian origin, and another of 355 carat from Ceylon.
Apart from listing all these gems of fabulous beauty and size, we cannot fail to mention the aquamarine of Emperor Don Pedro I of Brazil, discovered in the 1800´s, and renowned for its beauty, which has not been equaled yet by any other crystal.
Due to the scarcity of known deposits, the production of aquamarines remains low, and this, together with a growing demand, has elevated the price to dizzy heights.

Do you want to read about the Emerald as well? Click here!