For thousands of years, gemstones have fascinated humans. Is it any wonder when they’re so stunning to look at? That said, the allure of gemstones goes way beyond their aesthetic appeal. Instead, precious stones are impressive geological creations that have been forming over millions of years, and all of this is achieved by the forces of nature alone. Therefore, a true appreciation of the magnificence of gemstones means understanding the science behind how they were formed. It’s not just about crafting exquisite jewelry like designer cufflinks; it’s about knowing exactly where these gemstones came from and appreciating the marvels of nature.
Formation of Gemstones: Earth’s Masterpieces
Quite simply, gemstones are minerals that have gone through remarkable transformations deep within the crust of the Earth. In fact, the geological processes that are responsible for their formation are both fascinating and intricate.
- Heat and Pressure: The Crucible of Creation
Gemstones like diamonds are formed under extreme pressure and heat deep within the mantle of the Earth. This is achieved by the carbon atoms arranging themselves into a crystal lattice structure, which creates the hardest naturally occurring substance on Earth. These diamonds slowly rise to the surface via volcanic eruptions, which just proves how impressive the geological forces are. - Magma and Crystallization
Gemstones such as sapphires and rubies form in magma chambers beneath the surface of the Earth. As the magma cools and solidifies, the perfect conditions for the growth of mineral crystals are created. It is the impurities during crystallization and specific mineral composition that create the unique properties of gemstones. - Sedimentary Gemstones
Some gems, like opals, are created in sedimentary environments. Over time, cavities and crevices absorb silica-rich water, wherein microscopic spheres that diffract light are deposited. This then leads to the opal’s mesmerizing play of colors, characterizing the stones as a window into the geological history of the Earth.
Composition of Gemstones: Nature’s Palette
As previously mentioned, the captivating colors of gemstones stem from the presence of impurities and trace elements, as well as their chemical composition. As a result, a deeper appreciation of these natural wonders stems from an understanding of the fascinating chemistry.
- Color through Chemistry
The interaction between the trace elements and crystal lattice results in the coloration of the gemstone. For example, the blue of sapphires is a result of the presence of iron and titanium. Meanwhile, the green of emeralds stems from vanadium and chromium. Therefore, even the slightest change in chemical composition can lead to any number of colors within just one gemstone category. - Inclusions and Flaws
You seldom find a gemstone that is completely without flaws; however, the small imperfections that are otherwise known as inclusions are vital for the identification of authenticity. In fact, these imperfections are much like fingerprints, setting each gem apart from one another. Quite simply, the study of inclusions is one of the most vital aspects of deciphering the science of gemstones, otherwise known as gemology.
Unique Properties: Beyond Beauty
There are remarkable physical properties that make gemstones even more impressive than their aesthetic appeal. This is what contributes to their value in any number of industries.
- Refractive Index and Dispersion
A gemstone’s refractive index measures its ability to bend light. Since diamonds have a high refractive index, they create a beautiful sparkle. The separation of light into spectral colors, otherwise known as dispersion, is what results in the fire in gemstones like well-cut diamonds. - Hardness and Durabiltiy
Hardness is measured on the Mohs scale, and diamonds are the hardest gemstones, meaning they’re the most durable and resistant to scratches. As a result, they’re a great choice for jewelry that’s worn every day. - Cleavage and Fracture
Fracture characteristics are also unique to certain gemstones and it’s vital that gem cutters understand this so they’re fashionablegems without the cause of damage.