What’s the Difference Between Diamonds and Other Gemstones?

Both diamonds and gemstones are crystals of certain elements or compounds, but what’s the difference between coloured diamonds & other gemstones?

When we think about engagement rings and jewellery , the most popular stone to go with the precious metal of choice is a brilliant white diamond. At Diamond Heaven, we love diamonds (it's in our name after all). From shining black diamonds to sparkling yellow and even pale pink, diamonds are forever. Choosing to have a coloured diamond on your engagement ring or pendant might seem like a bizarre choice - especially when there are so many gorgeous gemstones to choose from out there. From beads of Jade for beauty, to dazzling blue Sapphires to a deep red Rubies, the intense colours of gemstones can transform a piece of jewellery - so why should you choose coloured diamonds such as a black or yellow diamond over them? Aside from the price tag of a coloured diamond, how do they compare to other gemstones? We thought we'd have a look into it! 

How are Gemstones and Diamonds Formed?

You may be wondering how diamonds and gemstones are formed. It should be noted to begin with that Diamonds and Gemstones are not mutually exclusive, as Diamonds fall under the umbrella term of "gemstones". All gemstones, including - Rubies, Emeralds and Sapphires are created between 3 and 25 miles beneath the earths surface under immense pressure. Diamonds, however, are formed much deeper.

Where are Gemstones and Diamonds Formed?

First things first, diamonds fall under the category of gemstones, and this is because all gemstones are crystals formed from certain compounds or elements. Alongside this, gemstones are rare and made naturally. This means that rubies, emeralds, sapphires, diamonds and so on are created in rocks found in the earth's crust, roughly three to 25 miles beneath the earth's surface. However, diamonds are formed much deeper in the Earth's surface.

Which Rocks are Gemstones Formed in?

The earth's crust is made up of three different kinds of rock; igneous, sedimentary and metamorphic. Each type of rock forms under different circumstances, resulting in the array of different gemstones we see.

Ingeous Rock

Igneous rock (also known as kimberlite) can be formed two different ways;
• The cooling and crystallization of magma beneath the earth's surface (intrusive or plutonic).
or
• Lava flowing to the earth's surface (extrusive or volcanic).
Which Gemstones form in Ingeous Rock?
Gemstones found in igneous rock include:
• Amethyst
• Citrine
• Ametrine
• Moonstone
• Diamond
• Tanzanite
• Topaz
• Zircon

How are Gemstones Formed in Igneous Rock?

Interlinking crystals grow within intrusive igneous rock, sometimes forming gemstones depending on the following three factors;
• Elements present,
• Cooling time,
• The environment.
In deeper environments, the slower cooling the larger the gemstone is.
To form a gemstone or crystal, the Kimberlite originates from the Earth's mantle (>125 miles) and stops at the Earth's surface. Molten magma with temperatures between 700 °C to 1300 °C runs through the kimberlite and then reaches the surface as lava. If the magma doesn't reach the surface, it cools more slowly, crystallising and forming coarse-grained minerals.

Sedimentary Rock

Sedimentary Rock is a rock formed by the deposition and successive cementation of the material at the Earth's surface within bodies of water. Sedimentation is the collective name for the processes that causes mineral and/or organic particles to settle in place.

Which Gemstones form in Sedimentary Rock?
Gemstones found in Sedimentary Rock include:
• Opal
• Zircon
• Jasper
• Malachite

How are Gemstones Formed in Sedimentary Rock?

Sedimentary gemstone happens when water mixes with minerals on the Earth's surface. Rock is worn down, and fragments of mineral rich water and wind seeps down into the cracks and cavities in the Earth's surface, depositing layers of minerals which are then compressed over time, forming gemstones.

Metamorphic Rock

Metamorphic Rock is formed when intense underground heat and/or pressure changes rocks that are already there.
Which Gemstones are formed in Metamorphic Rock?
Gemstones formed under these circumstances include:
• Emerald
• Aquamarine
• Jade
• Ruby
• Zircon

How are Gemstones Formed in Metamorphic Rock?

Metamorphic refers to the circumstances where heat and pressure change pre-existing minerals into something new. This means that the underground pressure forces minerals and elements that are already there to form into beryls.

The Formation of a Diamond Vs a Gemstone

One of the most significant differences between diamonds and other gemstones sits within the formation of a diamond. Diamonds are the only gem formed from a single element - highly pressurised carbon. All other gems are compounds of two or more elements. For example, sapphires are a variety of the mineral corundum, an aluminium oxide. The sapphire's intense colour comes from traces of elements such as iron, titanium, chromium, copper, or magnesium.

Why Do Diamonds Cost More than Other Gemstones?

Another notable difference between diamonds and other gemstones is the considerable price difference. Gemstones respond to normal market pressures - the prices go up and down with demand and supply, but this is not the case for diamonds. There is a monopoly on the price of diamonds, as they are held artificially high by a single company. Huge amounts of diamonds are also in storage in order to create a shortage and so keep the price up. This price manipulation is allowed in diamonds but prohibited for other gems and precious metals.

Is a Diamond Precious or Semi-precious?

The categories precious and semi-precious are 19th century terms that were coined in order to designate the value, beauty, rarity and popularity to gemstones. Gemstones have been known to switch between categories, such as the Amethyst, which was considered a precious stone until large deposits of the stone were discovered in South America during the 1800's. At present, there are only four jewels considered to be precious stones:
• Sapphire
• Emerald
• Diamond
• Ruby

Are Diamonds Naturally Clear?

The clarity of diamonds varies from stone to stone, but the clarity is not the only variant to consider. When researching diamonds you will more than likely come across the aptly named 4 C's. The 4 C's are Clarity, Cut, Colour and Carat and they form the framework which determines a diamond's price. Only some diamonds are naturally clear, and they come in a variety of colours, but the clearer a diamond is the higher the price generally is. This does not mean that coloured diamonds are of a low value however, to the contrary, the deeper the colour of a diamond the rarer and therefore more valuable it is.

Do you prefer coloured diamonds or gemstones? Let us know in the comments!