Gemstones have fascinated people since as long as we know. Those have been the witness of love and battles. These have graced the crowns of royals and the bags of robbers.
As you wear that diamond ring on your wedding, have you ever wondered where it actually came from? How did the ruby get its red hue and the sapphire its blueness?
The truth is, the way gemstones are formed in nature is really captivating to think of. A lot goes on and it is a matter of chance and probability for your perfect gem to be born.
How Gemstones Are Formed In Nature
So there are four ways gemstones form in nature, deep within the earth. We are not speaking of pearls and corals which are formed in the sea. So let us see what makes diamond, ruby, sapphire, garnet, opal and such gems.
Igneous- Diamond, moonstone, topaz, zircon and quartz are formed this way. This happens very deep in the earth.
Hydrothermal- In this way, gemstones are formed when bodies of water that is rich in minerals cools down in the crust. Think of emeralds.
Metamorphic- Sapphire, ruby jade, lapis lazuli, turquoise and garnet are formed this way. There is a lot of heat and pressure going inside the earth’s crust which shapes and forms beautiful gems.
Sedimentary- These type of gemstones are formed in a long time as water deposits its sediments with the right temperature and pressure. Malachite and Opal are sedimentary gemstones.
Generally a gemstone needs to be formed at least 3 miles (4.8 km) deep inside the crust. Most gemstones are formed 3 to 25 miles (4.8 to 40 km) deep within the earth. The gemstones that form in the deepest are the diamond and peridot.
It Is Literally A Sizzling Process
Imagine 150 miles (241 km) within the earth. It is the layer of earth what geologists call the mantle. It rests beyond the crust which is the surface of the earth.
This mantle is a storehouse of magma which can get hotter than 2120 F (1160 degree Celsius). However it is this scorching molten fire that will form the most scintillating diamonds!
This molten rock, the magma finds its way through natural fissures called kimberlite pipes. It rises towards the crust. Two things can happen now.
The magma may rise through the natural pipes and exit the surface as boiling lava. Or it can penetrate natural fissures. When the second phenomena takes place, the magma entering a fissure builds up unbelievably high pressure.
In the presence of abnormally high temperature and pressure, all impurities are shed off and a crystal structure starts to form. This is a purely carbon crystal. It is stored by the earth till the right time comes when it is extracted and admired by man.
Does Your Emerald Turn Others ‘Green’?
Wear a dazzling emerald necklace and it sure to turn many into green eyed jealous monsters. It has fascinated kings all across ancient Europe, Czars and Sultans. Shah Jahan is said to have been very attached to his emerald collection.
But do you know how does Mother Nature create an emerald? Deep within the earth, vein like crevices are present. Mineral laden water passes through these veins. With time, as temperature changes over its myriad paths, the over-saturated water deposits its minerals. With the right heating and cooling, beautiful green crystals start to form. Columbia’s Muzo Emerald mine is a fascinating place to see these emerald laden veins.
However the right gemstones are formed with right temperature, pressure, mineral content and a lot more factors. The crystalline structure, the impurities – there are several points. That is why gemstones can be placed in so many categories and price range.
How Gems Get Their Specific Colour
We know gemstones by their colour. We admire the red ruby, the blue sapphire, the green emerald and so on. Depending on the shade of the colour a gemstone is also valued.
What is it that gives a gem its colour, its shades?
The answer is light. It is the way a gem absorbs light that it gets its colour.
There are some rare gemstones that are idiochromatic. When the ray of light falls on a gem, and most of the rays pass through, it will be colourless, like a flawless diamond looks. On the contrary, if all colours get absorbed and none is reflected, the gem will appear black.
But take the case of peridot. The rays of light pass through it except the green wavelength. So it appears green in colour to our eyes. This happens because of their crystal and chemical structure which allows certain wavelengths to get absorbed.
Most of the gems also get their colour because of their allochromatic nature, that is because of trace elements or impurities.
A good example is corundum. Corundrum is a hard crystallized alumina. When corundrum is pure, it has no colour. But if it has chromium present in it, it gets a red hue and that is what we call a ruby. If the same corundrum has traces of titanium present it, it will appear blue and we call it the sapphire.
Likewise we have beryllium in emerald, chromium in tourmaline, iron in yellow sapphire, copper in turquoise and so on. However, colour of a gemstone can also be combination of one or more elements. Basically, colour is the result of the play between the crystal structure of the gem with the trace elements and impurities.
How do you identify a real gemstone from a fake
First of all gemstones will never have a sandy texture. Run your finger over a gemstone and you will see it never has a rough feel. Although it is difficult for a layman to identify a fake gem from a real one, but there are some tricks that you can try.
The gem is also never malleable, which means you cannot easily bend or crush it. A real one will break into pieces under pressure but a fake one will have change in its shape. Real gemstones have crystalline structure which can be cut and shaped only but not hammered or pressurized.
In the market there are also many synthetic gemstones being sold as real ones. The genuine gem is formed in nature but the synthetic ones are made in labs. Then there are also imitations, which are being sold off as real ones.
The synthetic and imitation gemstones on closer examination under a magnifying glass tells it all away. There could be gas bubbles, uneven surface, curved patterns inside (real one never have curves), and wispiness and many more telltale signs.
The most modern and efficient way to identify a real gem is to put it under a Energy Dispersive X-Ray Fluorescence (EDXRF) machine. It not only identifies real from a fake one but can also speculate from where it was mined. To determine its geographic origin it matches the trace elements, impurities and other relevant data.
Gemstones are as beautiful as these are fascinating in their crystalline structure. Wear it for beauty or luck, just remember that you are wearing molten magma from deep within the earth!