A Guide To Precious Gemstones

Where would our jewellery be without gemstones

Gemstones have an uniquely intoxicating character all their own and come in a tantalising array of colours. From sapphires to emeralds, diamonds to rubies, the colours make your precious jewellery radiant, distinctive and beautiful.

Even diamond, often thought of as a colourless stone, also comes in all the colours of the rainbow, each a unique individual with its own beauty, distinctiveness and colour. The way a gemstone is cut, meanwhile, harnessing the talent of the skilled cutter, will evoke and enhance the natural beauty of the gemstone.


Gemstones are rare. They have been created deep in the Earth’s core, through heat and stress over many, many millions of years. They are found in the harshest of places on Earth from emeralds in the steaming heat of Colombia to diamonds in the baking sun of southern Africa.


To resist the inevitable daily wear and tear yet retain its sparkle and beauty, a gemstone needs to be robust so here’s a little bit of science to help you assess the hardness of your chosen gemstone. Gemstones are ranked on the Mohs’ Scale and the higher the score on the scale the more scratch-resistant a gemstone is. Diamonds score a perfect 10, sapphire and ruby a 9, emerald a 7.5, while other popular gemstones score lower down on the scale and are, therefore, more fragile.

Jewellery gets a fantastic amount of wear. Even with its top Mohs’ score of 10, a diamond can still chip. Over the years, the facets on a ruby or a sapphire may wear while an emerald can chip or fracture. However, with careful treatment and regular checking by your jeweller, your precious gemstone will give you years of trouble-free wear.


It’s chemistry that creates the beauty in the precious gemstones we love. Millennia of heat and pressure cause these wonderful crystals to grow in the core of the Earth.
Rubies and sapphires, for example, are both corundum and it’s their unique chemical composition that gives them their distinctive colour. For a blue sapphire add titanium and iron; add a dose of chromium and you have a ruby. Emeralds and aquamarine are actually cousins in the beryl family: chromium gives us the intense green of emeralds while a sprinkling of iron produces aquamarine.


The clearer or ‘cleaner’ the stone, the more desirable

and valuable it is. The faultless gemstone is an incredibly rare – and special – find. But flaws, or ‘inclusions’, are tiny internal imperfections that reveal how the millennia have worked their own special magic to create totally unique gemstones with their own natural fingerprint and individual characteristics.


The gemstones and their colours: with gemstones, the array of colours is virtually limitless.


The ‘Prince of Gems’. Diamonds are the ultimate gemstone. Hard, durable, beautiful and with an unmatched sparkle.


The wonder of rubies and sapphires is they can be tailored to suit any taste. They offer a range of beautiful blues or ravishing reds yet there are yellow, pink and violet sapphires, too.


The emerald’s green is intense yet it’s a brittle, more fragile gemstone. Which is why the emerald-cut shape was developed to protect it.


Found only in Tanzania, the tanzanite marries purples and blues. Tender and tantalising.


Garnets are generally untreated and available in a myriad of sumptuous colours – red, mandarin orange and the intense green of tsavorite.


Radiant in its shades of purple, legend has it that this durable member of the quartz family can protect against inebriation!


Citrine is a quartz, the pale yellow to brownish-orange cousin of amethyst. Its attractive colour, durability and affordability make it the favourite yellow-orange gemstone.


Pearls are a delicate, natural, organic mineral, beautiful and shimmering with a shiny lustre created by the mollusc host where they grow. They are best worn or stored well away from other stones.


From pinks to oranges, topaz comes in an explosion of colours.


Opals are unique for their sheer play of colour. As cabochons, the curved surface helps this less durable gemstone survive knocks and scrapes.


Peridot is a uniquely apple green vitreous gemstone. The beauty of greens with small black inclusions surrounded by a halo gives it its affectionate name of ‘Lily Pad’.


As the name suggests, aquamarines were once thought to come from the sea, but they actually belong to the beryl family. Their long parallel needle inclusions are colloquially known as ‘rain’!


Tourmaline comes in green, blue-green, mint, yellow and even dusky pink.