Figure 1 : This depicts the rock cycle of the earth the critical function in forming gem stones.
It has always been part of society as they are worn to display the representation of social status or simply for its beauty. Humans have traded, looted, hoarded, waged wars, families torn apart to acquire various sorts of wealth and gemstones are not exception. Unmatched beauty, rarity and purity and endurance are the undying quality of highly priced gem stones.
Earth we live today in is one third the age of universe. Which is 4.54± 0.05 billion years. The earth has undergone many transformations for billions of years. Over the last millions of years, molten lava cools down to form the crust and the continents started to form lands, emerging from the seas. These Techtronic movement of creation and breakages made the perfect environment giving birth of these magnificent stones what we witness today.
The 9/10 of Sri Lanka is made of high grade metamorphic rock which means the 90% of Sri Lankan land mass belongs to Precambrian age is aging 3000 to 4000 Million years forming the very first layers of the earth.
Sri Lanka was originally part of southern Gondawana and subsequently broken off due to magmatic heat breaking the tectonic plates and moved the island to north with the Indian Plate. These metamorphic geology survived all these transformations has led to the small island shine as the jewel box of Indian Ocean. Island having a history that running back 2 billion years, there is no wonder Mother Nature has chosen Sri Lanka to bless it with a varied abundance of gem minerals that precedes the reputation of any other nation.
Corundum is the second hardest naturally occurring mineral known to man. This mineral is often called with a familiar name as Sapphires. Aluminum Oxide (Al2O3) is called in mineralogy circles, is formed by volcanic process deep in the earth where temperature and pressure are extreme. Continental drifts enable these temperature, pressure and mineral to flow in controlled environment to form these gems stones. When these extreme environment melts the minerals and isolates in the gaps of rocks, it slowly cools down over the hundreds and thousands of years to form crystals.
Structure of AI2 03
The purest and most translucent forms of corundum are created by recrystallization of minerals during the metamorphosis of rocks that are of igneous origin. It is a process that takes millions of years and only a few places in the world where rock outcrops where these rare crystals are exposed by weathering.
Crystal structure of Corundum
Purest of corundum are clear and colorless. Mineral impurities that seeps inside to the corundum during the cooling process gives the marvelous colors. Different colors triggered by the presence of different transition metal impurities. When trace amount of titanium and iron gets into Aluminum oxide produces the beautiful blue sapphires. Blue sapphire is one of the highly prized variant of the mineral corundum.
The rarest and the most precious gemstones are called pigeon blood rubies for its deep red color formed when right amount of chromium gets in. Sapphires naturally forms in different colors golden yellow, orange, pink, violet, green, white and even Black due to different composition of elements highly prized are free of intrusions and translucent or transparent.
For comparison, Gold is a naturally occurring element and it is priced for its rarity. Whereas, gems are combination of elements with right amount, pressured, undergone different temperature over thousands or even millions of years and seeping of mineral at right quantity and time makes them the rarest, valuable and magnificent gemstones demanding high price over any other mineral found on earth.
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