A World of Colour
While colourless diamonds are generally valued for how little colour they display, coloured gemstones are judged very differently. Here, colour is at the heart of both beauty and value. Hue, tone and saturation are among the most important factors, and colour alone can account for a significant part of a gemstone’s overall value. Carat weight, cut, clarity and origin also play an important role.
Rarity is equally important. Gemstones that combine exceptional colour with limited natural availability can command remarkable prices on the international market, particularly when they can be traced to a highly regarded geographical origin.
Yet the beauty of a gemstone is also deeply personal. Choosing a stone is not simply a matter of grades and measurable qualities, but of the colours you are drawn to, the character of the individual stone and the meaning it holds for you.
Corundum – Ruby and Sapphire
Ruby and sapphire both belong to the mineral family corundum, one of the hardest naturally occurring minerals. With a hardness of 9 on the Mohs scale, corundum is second only to diamond.
Ruby owes its characteristic red colour to traces of chromium and is among the most valuable coloured gemstones in the world. Often referred to as the “king of gemstones”, the finest rubies are prized for their intense, richly saturated red colour. The celebrated “pigeon’s blood” red is particularly associated with rubies from Myanmar. Exceptional examples can command some of the highest prices per carat of any coloured gemstone.
Sapphire is best known for its blue colour, which results from trace elements including iron and titanium. Corundum, however, occurs in a much broader spectrum of colours, including green, yellow, pink, orange and violet. These are commonly referred to as fancy-colour sapphires. Pink sapphire, for example, can offer an appealing alternative to a pink diamond, allowing for a larger stone at a considerably more accessible price.
Among the rarest varieties is the padparadscha sapphire, prized for its distinctive combination of pink and orange. Traditionally associated with Sri Lanka, these exceptionally rare sapphires are particularly sought after by collectors.
Quartz – Amethyst, Citrine and More
Quartz is one of the most abundant minerals on Earth and occurs in a remarkable variety of colours and forms. Among its best-known gemstone varieties are amethyst, citrine, rose quartz, smoky quartz and rock crystal.
With a hardness of 7 on the Mohs scale, quartz is durable enough for many types of jewellery. It is found throughout the world and valued for the variety of colours and levels of transparency found within the mineral family.
Amethyst is recognised by its violet to purple colour and has a long history of association with royalty and religious symbolism. Despite its rich colour and long history as a gemstone, amethyst is generally more accessible than many rarer coloured gemstones.
Citrine is the yellow to orange variety of quartz, appreciated for its warm colour and typically good clarity. Both amethyst and citrine are generally transparent and often have few inclusions visible to the naked eye.
The most common variety is colourless rock crystal, valued for its transparency and pure, clear appearance.
Topaz
Topaz occurs in a broad spectrum of colours. The rarest and most valuable varieties display natural red or orange-red hues, while colourless topaz is considerably more common.
Blue topaz is widely used in jewellery, although its colour is usually achieved by treating naturally colourless topaz. The treatment produces the range of blue shades for which the gemstone is known today.
Beryl – Emerald, Aquamarine and Morganite
Emerald, aquamarine and morganite all belong to the beryl family and are among its best-known gemstone varieties. Their distinctive colours are what set them apart, ranging from the rich green of emerald to the blue tones of aquamarine and the soft pink and peach shades of morganite.
Emerald is prized for its characteristic green colour. Lighter green varieties of beryl generally do not meet the colour criteria for emerald and are instead classified as green beryl, with a significantly different market value.
Unlike many other gemstones, emeralds commonly contain natural inclusions. These are traditionally referred to as the stone’s jardin, the French word for “garden”. Rather than simply being regarded as imperfections, they are widely accepted as part of an emerald’s natural character and individual appearance.
Aquamarine takes its name from the Latin aqua marina, meaning “sea water”, a reference to its blue to blue-green colour. Aquamarine can form in large crystals of high clarity, allowing for beautifully proportioned gemstones that often appear free of inclusions to the naked eye.
Morganite is the pink to peach-coloured variety of beryl. Its colour comes from traces of manganese and can range from delicate pale pink to warmer peach tones.
The beryl family also includes heliodor, known for its golden yellow colour, and goshenite, the colourless variety of beryl.
