Your guide to bi-colour sapphires
What is a bi-colour sapphire?
Known for their dazzling colour, many people associate sapphires with rich shades of blue and indigo, like the sapphire made famous by Princess Diana’s iconic engagement ring. But did you know that sapphires come in virtually every colour imaginable? From black to orange—or yellow, purple, peach, pink, green and every shade in between—the science behind these precious stones allows the earth to serve them up in a variety of ways.
Beyond that, there are even natural sapphires that contain a multitude of colours throughout the stone.
Bi-colour sapphires (also known as parti coloured sapphires) are gemstones that feature two or more distinct colours within a single sapphire. These gems are always one of a kind due to their organically produced colour.
Bi-colour sapphires are not two differently coloured stones that have been melded together—this is just the way the earth cooked them!
What colour is a natural sapphire? What colour is a bi-colour sapphire?
Similarly to diamonds, sapphires can be either grown in a lab or grown naturally in the earth over millions of years. The difference with bi-colour sapphires is that they cannot be synthetically produced. These beauties can only occur naturally.
You might be wondering: how does a sapphire get its colour? Classed as a precious gemstone, sapphires are part of the corundum mineral family, meaning they’re composed of aluminium oxide, iron, titanium, chromium, copper and magnesium. When combined under the immense pressure of the earth’s crust, these metals and minerals compress into sapphires. The colour of a sapphire is determined by subtle variations in the amount of each element found in and around the gemstone.
For example, a yellow sapphire is caused by high amounts of iron within the stone. More iron than titanium will create a green corundum stone, while more titanium than iron will give a sapphire a blue shade.
The location of these different elements and/or the changing composition of the surrounding earth and stone over millennia is what makes the alternating tones within bi-colour sapphires.
Bi-colour or parti sapphires are judged based on their ‘colour zoning’ (the location of the different colours), the colours’ contrast with each other, and their respective saturation. This spectacular variety is what makes parti sapphires such an exciting choice for an engagement ring: they’re as unique as the love story that inspired the ring in the first place.
Are bi colour sapphires rare?
Bi-colour sapphires are much more rare than single toned sapphires as they only occur within a perfect storm of geological conditions that can’t yet be replicated in a lab.
That being said, bi-colour sapphires tend to occur anywhere natural sapphires are found, although in some locations more than others. Australia is known the world-over for its abundance of bi-colour sapphires, and many teal and blue-green bi-colours come from the ancient riverbeds of Montana, USA. At Taylor & Hart, we source most of our parti sapphires from the famous Ratnapura region of Sri Lanka. You can read more about our incredible team in Sri Lanka and their sapphire expertise here.
The most common colour pairing amongst bi-colours is green and yellow. Sometimes the two colours will evenly split within a stone, and sometimes they are mottled together like a tortoise shell motif. The rarest combinations are those that contain powder blue, cornflower blue, or purple shades. Some stones have been known to exhibit pink, orange or silver tones as well, and these are especially desirable because of their sunset-like tonality.
Is a bi-colour sapphire a good choice for an engagement ring?
The short answer: 100% yes.
But despite their dreamy, one-of-a-kind appearance, bi-colour sapphires remain relatively unknown within the jewellery market. However the popularity of coloured gemstones has spiked recently, making them one of the top engagement ring trends of the past year. Could this golden age of colourful wedding jewellery finally allow bi-colour sapphires to take centre stage?
Sapphires are an incredibly durable gemstone, making them ideal for everyday wear. In fact, sapphires score a 9 on the Mohs mineral hardness scale (a measure of the resistance of materials against scratches of harder materials), meaning they’re second only to diamonds in terms of durability. You can be confident that your parti sapphire engagement ring will last a lifetime.
When choosing a bi-colour sapphire it’s best to work with a gemstone expert or jewellery designer in order to find a stone with the most suitable cut for your design, along with the best colour pattern. Another interesting thing about bi-colour sapphires is that they’re commonly cut in artistic and creative shapes—more so than their single tone counterparts. This is because a cutter will study a rough bi-colour sapphire’s colour pattern and cut the stone to best feature the colours rather than retaining the most carat weight.
This bi-colour sapphire features a subtle combination of blue, green and chartreuse
Looking to create a custom bi-colour sapphire engagement ring? Get in touch with our team of design specialists who can help you find your dream gemstone and talk you through all the ins and outs of making a personalised coloured gemstone ring.