A Guide to Natural Coloured Gemstones
Natural coloured gemstones, chosen one by one
At GIOIA Fine Jewellery, we source natural coloured gemstones from around the world, from Muzo green emeralds of Colombia to vivid sapphires of Sri Lanka and the neon Paraiba tourmaline of Brazil. Our co-founders, Clarence and Cheryl, hand-select every stone together, looking at colour, clarity and cut before it joins our selection. We hold one of the widest selections of natural coloured gemstones in Singapore, with over 2,000 stones on hand, so clients can compare several before choosing.
Written by Clarence Yee, co-founder and gemstone specialist at GIOIA.
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Where Our Gemstones Come From
Whether you are planning customised jewellery or a gemstone engagement ring, we can show you stones from many of the world’s important sources. Our collection features Colombian emeralds, Sri Lankan and Burmese sapphires, Mozambique and Burmese rubies, spinels from Burma and Tanzania, including vivid Mahenge spinel, and Paraiba tourmalines from Brazil and Mozambique, among many others.
Gemstone Jewellery
Our wide variety of precious gemstones, including emerald, sapphire, ruby, spinel and Paraiba tourmaline, gives us room for creative, bespoke designs. We have made many pieces, from traditional heirloom jewellery to modern fine jewellery for everyday wear. We work with you personally, from the first design consultation to the finished jewel.
Choosing a Gemstone for Your Rings
Coloured gemstones are increasingly popular with couples looking for a unique proposal ring. You can build a customised engagement ring around a gemstone in your partner’s favourite colour, which gives it extra meaning. With a wide range of colours and shapes, our designs range from floral to geometric Art Deco gemstone wedding bands. Birthstone jewellery can also combine the birthstones of the people you love, and become an heirloom for generations to come. We are happy to share more ideas for your wedding ring, and you can chat with us using the live chat at the bottom of the screen.
To explore our full collection of bridal designs, visit our gemstone engagement ring gallery.
What Determines the Value of a Coloured Gemstone?
Rarity
One of the key factors that determines the value of coloured gemstones is rarity. Paraiba tourmaline from Brazil shows how some gemstones can be rarer, and more expensive, than diamonds. In our experience, fine unheated Brazilian Paraiba trades at roughly US$15,000 to 50,000 a carat, well above many 1ct diamonds.
Similarly, alexandrite was first found in Russia’s Ural Mountains, and today also comes from Brazil and Tanzania, as well as Sri Lanka and India. We hold Russian alexandrite as well as stones from these newer sources. Alexandrite remains one of the rarest gemstones on Earth. Its colour change, from green or bluish green in daylight to red or purplish red under warm indoor light, makes it highly sought after and adds directly to its value. Rarity like this is what sets these gems apart, which is why fine Paraiba tourmaline and alexandrite are among the most expensive gemstones on the market.
Rarity also explains why a fine precious gemstone, such as a top emerald, is valued far above a more common gemstone of similar size, however well the common stone is cut.
When comparing gemstones of the same type, several factors decide their value: colour, origin, enhancement, carat, clarity and cut. Each has a large effect, and together they give a full picture of the stone, but it is the combination of rarity and quality that sets the finest gemstones apart.
Colour
Colour is the most important factor in a gemstone’s value. As a general rule, value rises with colour intensity, as long as the colour stays vivid and does not turn too dark. Once a stone becomes so deep that it looks almost black, its value drops sharply.
Many people consider the rich, slightly bluish green of a fine emerald the most beautiful green of all. Green sapphire and tsavorite garnet can be lovely too, but their green is different in character, and every gemstone has a colour of its own.
If you’re seeking a blue gemstone in a vibrant royal blue or cornflower blue, consider the blue sapphire instead of the often expensive cobalt spinel, as in our view its premium doesn’t offer proportional value. Cobalt spinel from Tanzania and Sri Lanka has drawn a lot of attention, but in our experience the rarest cobalt spinel comes from Luc Yen in Vietnam. We have also seen prices for Tanzanian cobalt spinel drop significantly in recent years, after reaching US$10,000 to 15,000 a carat.
Origin and Enhancement
When grading major gemstones such as ruby, sapphire and emerald, origin and enhancement have a large effect on value. For example, a fine Kashmir sapphire can cost many times more than a Sri Lankan sapphire of similar colour and size, and an unheated pigeon blood ruby usually costs considerably more than a heated pigeon blood ruby of similar colour and size, because far fewer rubies reach that colour without heat.
Heat treatment is common across both precious and semi-precious gemstones. In aquamarine, gentle heating removes a greenish or yellowish tint to leave a purer blue. In sapphire, heating can dissolve the fine needles that make some corundum look milky and dull, turning it into a clear, attractive blue. Getting the heating right matters just as much. The result depends on how hot the furnace gets, how long the stone stays there and how slowly it cools, and badly controlled heating can leave a poor colour or even crack the stone. It is also why a fine unheated sapphire is so valued, because it reached its colour on its own.
Clarity
Gemstones grow as crystals from natural minerals, and their crystal structure shapes properties such as hardness and how light travels through them. Disturbances during growth leave inclusions, such as feathers, crystals and needles. Inclusions can help a lab trace a stone’s origin and spot signs of treatment, and they can also help tell a natural gem from one grown in a laboratory.
Some inclusions even add to a gem’s appearance and value. Cat’s eye chrysoberyl and star sapphire and ruby owe their effects to fine needle inclusions.
Crystal Shape and Cut
Each gemstone tends to grow in its own characteristic crystal shape, depending on the conditions it formed in. These shapes help tell rough stones apart, for example ruby from spinel, or tourmaline from red garnet.
Coloured gems come in many cuts, and some shapes are closely linked to particular gems, such as the round brilliant for diamond and the emerald cut for emerald. The shape of the rough usually guides the shape and size of the finished stone, and with rare, expensive gems the cutter aims to keep as much weight as possible.
How We Choose Gemstones at GIOIA
Our priority is quality rather than quantity. When we buy a gemstone, we weigh the factors discussed above: colour, origin, enhancement, carat, clarity and cut. Every natural stone is unique, so no two are ever exactly the same. As CNA Lifestyle has reported, coloured gemstones have become increasingly popular in recent years.
A stone with vivid colour that is also unheated may not come in a perfect shape, and a stone with an ideal cut and size may not be flawless. Choosing a coloured gemstone always involves some balance between these qualities, and we help you decide what matters most to you.
We guarantee that every gemstone we sell, such as emerald, sapphire, ruby and spinel, is natural and exactly as described. When you receive your finished piece of bespoke jewellery, every centre stone above about SGD 1,000 comes with a report from an independent laboratory such as GRS, GIA or NGI, which confirms whether the stone is natural and whether it has been treated, and can also state its origin. An independent report gives you a fair and neutral view of the stone.
Birthstones and Other Gems
The tradition of birthstones goes back centuries. Alongside our main gemstones, we also offer birthstones such as garnet and moonstone, so a family piece can include every month. We choose them the same way as our other stones, for good colour and clarity.
Final Thoughts
With the rise of factory-made lab-grown diamonds, coloured gemstones have gained even more prominence as rare and lasting choices for fine jewellery. Precious coloured gemstones, with their rich history spanning thousands of years, are cherished as beautiful jewellery, and at the fine end they are valued for their rarity. Fine jewellery is built on rarity and scarcity, and in our experience more people discover fine coloured gemstones every year. If you’re weighing a coloured gemstone against a diamond specifically, our gemstone vs diamond engagement ring guide breaks down hardness, value, and ethics in detail.
That said, it’s essential to be well informed when choosing a gemstone, whether for yourself or as a gift. A clear example is cobalt spinel, where, in our view, heavy marketing pushed prices well above what the stones offer. At GIOIA, we aim to guide you with knowledge and experience, so you can make an informed choice when buying your next gemstone.
Explore our collection of rare gemstones and find the piece that suits your style. Chat with our team for a personal consultation and to begin your custom jewellery journey. Because we source gemstones every year, we can share what we see in the market and help you choose with confidence.
Frequently Asked Questions
Find answers to common questions about coloured gemstone jewellery.
What factors determine the price of coloured gemstones?
Several factors influence the price of coloured gemstones, including rarity, colour intensity, origin, enhancement, clarity, and cut. Together, these elements create a complete picture of a gemstone’s value, with colour usually mattering most. For important stones, a report from an independent laboratory confirms what you are buying.
Why is colour important when selecting a gemstone?
Colour is the most critical factor in determining a gemstone’s value. A vivid, intense colour is highly desirable, while overly dark or deep shades may reduce a gemstone’s value. For example, the rich green of an emerald or the royal blue of a sapphire are prized for their striking hues, setting them apart from other stones. However, personal preference also plays a role in selecting the right shade for you.
What is gemstone heat treatment, and does it affect value?
Heat treatment is a common, accepted and permanent way to improve the colour and clarity of many gemstones, especially sapphire and ruby. A heated stone is still natural, and fine heated stones can be very beautiful. At the same quality, though, an unheated stone is much rarer and usually costs more. Emeralds are treated differently, usually with oil to improve their clarity.
What is the significance of clarity in gemstones?
Clarity refers to the presence of natural inclusions or imperfections within a gemstone. While inclusions are common, gemstones such as sapphire and ruby have inclusions that add to their uniqueness and can even be used to trace their origin. Gemstones with fewer inclusions are generally more valuable, but exceptionally rare gemstones like Brazilian Paraiba tourmaline or alexandrite may still command a higher price despite their inclusions due to their rarity.
Why do some gemstones not sparkle?
Gemstones sparkle when light enters them and reflects back to the eye, which is known as brilliance. A poorly cut gemstone returns less light, so it looks dull. Inclusions, which are small natural features or fractures, can also block or scatter light and reduce brilliance.
Will a gemstone lose its shine over time?
Yes, gemstones can lose their shine temporarily, especially with the common hand sanitisers, hand creams, or oils from your skin. These substances can build up on the surface, making the gem look cloudy and dull.
Regular cleaning is key to keeping your gemstones looking their best, as it helps remove that buildup and restores the shine. At GIOIA Fine Jewellery, we offer lifetime cleaning services to ensure that your gemstones stay brilliant and beautiful for years to come.
Do gemstones have healing effects?
There is no scientific proof that gemstones have healing effects, but many people find comfort in these beliefs, for example using gemstones in meditation or wearing one as a personal talisman. At GIOIA Fine Jewellery, we believe what matters most is the meaning a gemstone has for you and how much you love it.
Do gemstones hold their value?
In our experience, yes. Rarity and scarcity are the core drivers of gemstone value. Fine-quality, unheated, and rare gemstones (like unheated sapphires or pigeon blood rubies) are limited in supply and highly sought after, which is why fine examples have held their value and become harder to find. We buy these stones ourselves every year, so we see the price movements first hand, though this is our own observation and not a guarantee. In contrast, low-quality or common stones rarely hold long-term value.
Have a question about coloured gemstones?
If you have any other queries, feel free to reach out to us. Our GIOIA team is here to help!
Beyond the gems above, we also work with mandarin garnet and morganite, and craft fine pearl jewellery for clients who want something beyond coloured stones.
A couple more from recent commissions: a Morganite Engagement Ring and a Morganite Wedding Band.