However the popularity of coloured gemstones has spiked recently, making them one of the top engagement ring trends of the past year. 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.īut despite their dreamy, one-of-a-kind appearance, bi-colour sapphires remain relatively unknown within the jewellery market. 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.īi-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. More iron than titanium will create a green corundum stone, while more titanium than iron will give a sapphire a blue shade. The colour of a sapphire is determined by subtle variations in the amount of each element found in and around the gemstone.įor example, a yellow sapphire is caused by high amounts of iron within the stone. When combined under the immense pressure of the earth’s crust, these metals and minerals compress into sapphires. 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. The difference with bi-colour sapphires is that they cannot be synthetically produced.
Similarly to diamonds, sapphires can be either grown in a lab or grown naturally in the earth over millions of years.