Precious Stones

By Natascha Trolle Gemmologist FGA –

Why compromise authenticity and strive for homogeneous perfection when you can go for natural beauty?

The miracle of gems.
Throughout history, gems have always had a touch of mystic to man. They have enchanted with their brilliance and extraordinary colours.

Most gems are formed in the earth’s crust, which has a thickness around 50 km.
Here, high pressure and release, drastic temperature change and small explosions take place and give birth to gems in an ongoing geological process.
During millions of years gems grow and form their own characteristic crystal shapes that you may be lucky to find hiking in the mountains or walking along a riverbed.
You may find Turmaline as long triangular plenty-coloured sticks or garnet as 12-sided brownish-red balls.
These beautiful and extraordinary symmetrical shapes in rough pieces of gems are due to the regular, repeating, 3-dimensional arrangement of the atomic bonding that exists in the material.

(Gemas = precious stone)
The study of gems is today a recognized science but has, like the science of psychology, existed for only a little more than a century.
Through thousands of observations and experiments with discoveries in mines and riverbeds, man has reached a far greater knowledge about how gems were created.

Precious and semi-precious stones.
Ruby, Sapphire, Emerald and Diamond were the “classical” precious stones, because of their beauty, durability, rarity and therefore their high value.
Aquamarine, Turmaline, Topaz, Garnet, Moonstone, Peridot, Spinel and the Quartzes Amethyst, Citrine, Rose-and Smoky quartz were considered semi-precious and the occurrences were and are also greater.
The terminology in gemmology has left this distinction because a low quality Ruby can easily be overtaken in beauty and value by a good amazingly green Peridot.

Inclusions, Rarity and individuality.
When dealing with natural gems, it is important to remember that they are unique and may not have a totally homogenous counterpart.
There may be what appear to be clouds or breakings in the stone. These are called inclusions. To name these inclusions as defects is somehow a misunderstanding.
What is more close to the truth would be to designate the creation of gems as a result of a defect -a very rare coincidence of circumstances in the geological processes.
Gems are actually a result of a statistic geological miracle, and that is also the reason why we are not wandering about in Aquamarines, when we take a stroll along the beach….

Inclusions can be cavities or fissures, eventually filled with gas, liquid and elements like iron, chromium or carbon and these inclusions can be one of the most important clues to the gemmologist´s work of identifying the stone.

Inclusions give the stone individuality, and can be remarkably beautiful, but they should not reach the surface of the stone. If the same inclusion becomes superficial two places, the value is reduced and there is greater risk that the stone may break when set in jewellery.
But there are many examples of inclusions placed inside the stone that enhance the light and increase the beauty and value of a gem. An example of this could be the beautiful Blue Moonstone.
Natural Emerald does not exist in bigger sizes without a certain amount of “herb garden” as it is pronounced. The observation in magnification of the phenomenon is an important tool in judging the origin of the Emerald.

Multitude of colours.
Ruby and Sapphire are in the same crystal family, as they are both an impure version of the crystalline chemical compound called Corundum.
When Corundum forms and crystallizes in its purest form, it is colourless.
This chemical compound is called aluminum oxide. When chromium bonds with aluminum oxide, the material appears red and is called Ruby. When iron and titanium bonds with aluminum oxide, the material is called Sapphire.
The blue Sapphire is the most well-known, but this stone can be yellow, green, pink, black violet and orange.
The chemical element that dominates in the bonding to aluminum oxide decides which colour our eyes perceive.

Imitations, Artificial and Synthetic Gems.
Man’s imitation of gemstones has been going on for more than 5000 years.
Glazed steatite and faience were used in the old Egypt to imitate Turquoise.
Later we invented production of glass to imitate the transparent stones.
Glass is still widely used as imitation.
Natural stones are also used to imitate, for instance Zircon is often a diamond stimulant..
Artificial = man-made stones vary a lot but may be, to the layman, very convincing as imitations.
Synthetic stones are next step on the ladder. For a stone to be called synthetic, is has to have the same chemical composition and the same atomic structure as its natural counterpart.
Within the last decades the technology around production of synthetic gems has developed greatly. Synthetic production reveals characteristic evidence of strain in the form of characteristic inclusions in the gem. They have been carefully categorized within gemmology but you still need some experience in order to identify them.
Even though the synthetic production aims to imitate the inclusions characteristic of natural stones, it is still common, that the synthetic stones look extraordinary perfect.

The origin of Gems.
I have described that most of the gems are formed in the earth’s crust. Therefore it is possible with some experience to see with magnification which country or continent the coloured gem may come from.
An important exception to this is Diamond. Until very recently man knew very little about the creation of Diamond. This is because Diamond is created further down in the mantle of the earth. It is therefore not possible, even for the most experienced expert to tell from a facetted diamond from which country or on which continent it was found.

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