How Are Gemstones Formed? A Complete Guide to Gem Formation

The alchemy of precious-stone crystals comes from the natural laboratory of the Earth, subjected to extreme geological conditions. Born out of crushing pressure, high temperature, tectonic movement, and chemical reactions, gemstones are an indispensable and valuable gift of nature. But are you aware that no two gemstones share one common formation process and profile? Yes, the diamonds and quartz sitting next to each other in a similar necklace have far different origins. This is where the actual need to understand the gemstone formation process truly begins. 

What Are Gemstones Made Of?

A gemstone crystal is an inorganic solid mineral compound that is valued for its beauty, durability, and appealing optical illusion. It is composed of atomic compounds bound in a crystalline structure by intense heat and pressure. The size and bonding of atoms determine the hardness and crystal framework of a gemstone. A crystal formation requires 5 formative factors to come into existence.

• Right Balance of Chemical Compounds
• Ideal Temperature
• Ample Pressure 
• Patience 
• Space to Bloom

Together, these five factors align to bring atoms into the right configuration to form the regal charm of a crystal under nature's craftsmanship.

How Are Gemstones Formed? The 4 Main Processes of Gemstone Formation 

The story of gemstones begins long before the existence of mankind. They are born in the natural laboratory of Earth between molten fluids, rigorous pressure and high heat. Every single gemstone has its own geological pathway and formation cycle. A few may originate from bubbling lava, while others might come along a flowing river. This process decides the physical and chemical composition of a gemstone. The four most notable crystal composition methods include igneous, hydrothermal, metamorphic, and sedimentary gemstone formation. 

Igneous Formation 

A range of fine gemstone crystals comes from the furnace of the earth. Deep beneath the surface, intense temperature shifts melt rocks and turn them into a thick liquid substance called magma. This boiling substance moves upwards and comes out in the form of lava, causing volcanic eruptions, fractures, ocean crusts and several other geological mechanisms. Once the heat fades away, the liquid substance starts cooling and turns into diverse structures. With the passage of time, these rock structures become gemstones due to several chemical and environmental factors.

Precious gemstone crystals like diamonds, rubies, and sapphires form under extreme geothermal energy carried by magma toward the Earth's surface. One can consider magma as both the birthplace and the catalyst that carries these stone crystals and brings them out from subterranean depths.

• Peridot
• Diamond
• Tourmaline
• Moonstone
• All types of quartz
  

Hydrothermal Formation 

The science of hydrothermal gemstone formation describes water as the primary alchemist. Inside the natural laboratory of Earth, heated water passes through layers of rocks and deposits, gathering all the mineral elements and dissolving them into a mineral-rich fluid. This substance travels through several cracks, and the surrounding rocks absorb its heat, reducing the temperature naturally. The cooling deteriots water ability to hold minerals decreases, and they eventually get deposited in cracks between stones. With the passage of time, the crystalline dust turns into varied structures, leaving behind precious gemstones like quartz and amethyst.

• Amethyst
• Citrine
• Emerald
• Aquamarine
• Fluorite

Metamorphic Formation 

Metamorphic gemstone formation is a process of geological transformation and temperature shifts. The tectonic movements of plates displace the rocks from their position, moving them deep below Earth's surface. At the depth of the crust, the intensity of heat is extremely high, which causes a definite shift in temperature. Under this geothermal reaction, the atomic structure of minerals present in rocks starts changing, attaining different compositions and colours. 

Sometimes two neighbouring rocks can also undergo chemical diffusion of minerals, giving a third variety of stone. This extreme subterranean process gives birth to a few of the most precious crystals like rubies and garnets. The scarlet red shade and fiery glaze of the finest rubies come from this intense transformation of aluminium rocks and traces of chromium deposits. 

• Ruby and Garnet
• Sapphires
• Tanzanite
• Jadeite
• Staurolite
  

Sedimentary Formation

Unlike other gemstone formation processes, sedimentary formation is the method of accumulation of minerals. When organic substances break down in rocks due to rain, erosion, or weathering, they settle on the surface and near-surface areas like basins, lakes, and estuaries. With evaporation, water loses its hold on these compounds, and the ions start bonding together. Gradually, the layers of deposition accumulate on each other and start getting into shape. Here, the amount of pressure and heat involved are key determinants of how a crystal looks.

• Opals
• Amber
• Jasper
• Agate
• Jet

How Are Crystals Formed in Nature?

Let's understand the process of crystal formation through the rock candy analogy. Imagine dissolving sugar in a glass of hot water; it will mix well. But as the water loses its warmth, it lets go of the sugar molecules. As a result, the dissolved sugar molecules begin to gather and get attached. Later on, the sugar crystals will grow and become more defined.

Simultaneously, when mineral-rich fluid loses water under the earth, the shreds of elements start blending. This uneven atomic structure sitting in rocks and geodes under the right temperature, pressure, space, and time transforms into the beauty of gemstone crystals.

How Do Minerals Form?

Minerals are inorganic substances formed naturally by geological processes. They usually have a solid, crystal-like structure and definite chemical composition. When tiny atoms and elements come together under extreme heat and pressure, they attain a definite structure over time. At times, they come out along with magma or are left behind by running water. 

Gemstones vs Minerals: What's the difference?

The opulent beauty and rarity of gemstones are classified in the category of minerals. However, it is important to understand that not every mineral gets the refinement to be called a gemstone. It is the primary and major factor that differentiates a gemstone from an average mineral.

All gemstones are minerals, but not all minerals are gemstones. Simply put, a gemstone is a type of mineral or crystalline structure that is beautiful, strong, and intricate with the natural artistry of Mother Earth. For example, both ruby and sapphire come from corundum, a mineral crystal of aluminium oxide. However, what differentiates them is the colour and quality of corundum.

Mineraloids are substances that fail to encompass the structured atomic profile required to be classified as a mineral. What truly differentiates a mineraloid from minerals is chemical composition, crystallinity, and physical properties. Stones like pearls, opal, jet, and Amber are a few commonly known mineraloids used to craft fine jewellery and ornamental accessories.

Where Do Gemstones Come From? 

Diamonds

Jwaneng Mine in Botswana is home to the finest and richest diamond deposits. The treasured land of South Africa hosts premium mining locations like Cullinan, which adorns the top of the British Sovereign's Sceptre. Mir Mine is another prominent mining location located in the Sakha Republic of the Russian Federation.

Emeralds

This mystical green stone comes from notable mining sites in Colombia and Zambia. In fact, the Muzo and Chivor mines of the Boyacá region in Colombia are known to produce 80-90 % of total emeralds, making it the emerald capital of the world. 

Rubies and Sapphires

The world's finest corundum deposits are mapped at a few treasured locations, including the world-famous Mogok Valley (pigeon's blood Rubies) of Myanmar, the islands of Sri Lanka and the Padar region of Kashmir. 

How Long Does It Take for Gemstones to Form?

A gemstone's journey runs deep back into the past, up to millions of years ago, where its origin truly begins. Yes, the natural artistry of Mother Earth runs extremely slowly while creating these beautiful crystals. It takes years of resilience and patience under extreme heat, pressure, and temperature for a single gemstone to come into existence. 

Precious stones like diamonds are formed over billions of years under the depth of the Earth's crust. This makes them extremely rare and immensely valuable among all other gemstones. On the contrary, opals are formed when silica-rich fluid fits into the cracks and fractures, creating deposits under favourable environmental conditions. Each gemstone undergoes a long passage of time before reaching us. This makes them an embodiment of determination and virtue that can be felt through their beauty and aligned energies. 

How Are Lab-Created Gemstones Made vs Natural Gemstones?

The major difference between natural and lab-grown gemstones lies in their formation, rarity, and value. While natural gemstones are born out of nature's lap, synthetic gemstones are made in laboratories using mechanical support and have a chemical composition similar to the original ones.

There are several notable factors that effectively reflect the true differences between natural gemstone crystals and lab-grown ones. The primary one is rarity. Precious gemstone crystals derived from the earth are scarce in nature. They are in high demand and valuable, which makes them expensive to afford. Whereas, scientifically derived gemstones can be customised as per requirement, making them accessible at more economical prices. 

Another important aspect to measure is the quality criteria. The colour grading, cut, clarity, and size are important elements to take into account. On the one hand, naturally occurring gemstones have diverse colour grading, non-uniform structure, and evidence of nature's artistry; synthetic gemstones have a definite structure, uniform colour patterns, and a bright, intense appearance. 

Ultimately, the actual difference between natural and lab-grown gemstones lies in their rarity, origin, prices, quality, and attributes. Original stones range higher than mechanically produced ones, justifying their characteristics and beauty.

Frequently Asked Questions

How are gemstones formed in the earth?

The formation of precious gemstones requires a favourable blend of the right chemical compounds, ample space, ideal temperature, balanced pressure and its own sweet time to come into existence.

What are the 4 ways gemstones can form?

Primarily, all gemstones emerge from either igneous, metamorphic, hydrothermal or sedimentary methods of crystal formation.

Are gemstones rocks or minerals?

All gemstones are made up of mineral compounds, thereby belonging to the mineral family.

How are crystals formed in nature?

The balance of chemical, physical, and geological attributes shapes the mineral elements into diverse, beautiful structures, bringing gemstones into existence.

How are diamonds formed?

The alluring diamond crystal undergoes a formative life cycle of billions of years to come into existence. They are made from compactly packed carbon atoms that give them an unbreakable hardness.

Can all minerals become gemstones?

Unfortunately no. Not all minerals can be classified as gemstones. A mineral crystal should meet the scientific criteria defined to be classified as a mineral.

How long does it take for a gemstone to form?

Gemstones are nature's most prized possessions, and it takes its own sweet time to form them. An average timescale of gemstone formation can range from a few thousand years to long cycles of millions.

What is the difference between natural and lab-created gemstones?

A natural gemstone is an inorganic substance derived from mineral elements under favourable geological conditions. Synthetic or lab-grown gemstones are produced in laboratories to imitate the physical, chemical, and optical characteristics of a natural gemstone.

Where do precious stones come from?

Located in the depths of Earth's core, all precious stones are derived from mineral deposits under high temperature and balanced pressure.