Bicolour Tourmalines: This Trending Gemstone is a Collector’s Dream

Displaying a sublime harmony of hues within a single stone, bicolour tourmalines are rare, unusual and very much on trend. A standout stone at the recent JCK and Couture shows in Las Vegas, these fascinating quirks of nature have a stunning visual impact when used in jewellery designs. KaterinaPerez.com contributor Claire Roberts takes a closer look at these intriguing conversation starters to find out what causes their unique colour zoning and speaks to the jewellers who celebrate their curious beauty.

I have been fascinated with bicolour tourmalines ever since I was shown a spectacular pendant by the esteemed American art jeweller Paula Crevoshay at the Couture Show in Las Vegas in 2014. I’d never seen a gemstone like it, with this specimen resembling a slice of fruit with a red centre and green outer layer. Dubbed watermelon tourmalines, Paula was my introduction to this natural phenomenon that occurs in several gemstones, including sapphires and ametrines, but is particularly prevalent in tourmalines. Ten years later, the popularity of tourmalines has skyrocketed. With one of the broadest colour palettes in the gemstone world, they offer jewellers the chance to experiment with the whole spectrum of hues and, in the case of bicolour tourmalines, stones that exhibit more than one colour in a single gem.

What Causes Colour Zoning  

The twin hues in a bicolour tourmaline are a brilliant fluke of nature. Usually displaying a gradient of colours that transitions from one to the next, combinations of green and pink are the most frequently occurring; however, colour-zoning combinations range from purple-pink and pink-blue to purple-green. But what causes this two-colour effect in bicolour tourmalines? Science has the answer. There are more than a dozen species of tourmaline, with almost all gem-quality stones belonging to the elbaite group. This species of tourmaline forms in cavities within pegmatites—rare, granite-like rocks that are rich in boron and lithium, elements that are essential to the formation of tourmaline crystals.

Growing in an environment that is rich in liquids, the tourmaline crystals absorb different trace elements that influence their physical properties and determine their colour. The distinct colour zoning of a bicolour tourmaline occurs when the liquid supplying nutrients to the crystal changes in composition or concentration during its growth. Put simply, trace elements are responsible for a tourmaline’s hue, and when a tourmaline crystal is exposed to different elements over time, it will naturally change colour during the formation process. 

Designing with Bicolour Tourmalines

Lisa Nikfarjam, founder of Lisa Nik, began using bicolour tourmalines in her collection five years ago. “People were fascinated,” she says, “and they have been an identifying feature of my brand ever since.” When she first encountered bicolour tourmalines on a trip to Brazil—the most significant source of tourmalines in the world—she imagined sitting on the beach sipping a cold fruit smoothie and wearing this stone against sun-kissed skin. “When I select gems to use in my collection, I look for the power the stone has to take my mind on a journey,” Lisa explains. “It seems like many others agree because they are a huge trend in jewellery right now.” Lisa loves working with watermelon tourmalines—stones that transition from pink to green—alongside pink and purple variations and brownish-green gems, which she has named ‘Mai Tai’ tourmalines. The cocktail comparison couldn’t be more appropriate, don’t you think?

Tourmalines are Antwerp-based designer Salima Thakker’s favourite gemstones, too, particularly the bicolour variety. “The power of nature is visible in a bicolour tourmaline,” she says. “It is not possible to reproduce this in a lab, and the distribution of colours is always different, which means each gem is unique.” Salima seeks out stones that display a gradual variation of colour and designs jewels around them that softly emphasise the different hues. “Bicolour tourmalines are stunning and rather loud,” she explains. “The classical style of my designs ensures that all eyes are on the gemstone.” While they are definitely not a shy and retiring gemstone, the fact that no two are the same inspires the designer Lauren K, who is based in New York City. “We enjoy that each and every watermelon tourmaline is as unique as the person who wears it,” says Lauren. “We find them so juicy!”

A New Era of Bicolour Tourmalines

Recently, the British jeweller Garrard propelled the bicolour tourmaline into high jewellery territory with the creation of the Couture Sunset suite, which features a unique collection of gems that transition from pink to grey to black. While many designers opt for pared-back settings, Garrard’s Sunset suite highlights just how theatrical these gems can be when partnered with other stones, in this case, black spinel and rose quartz, complementing the colours captured within the tourmalines.

In Las Vegas, we also spotted bicolour tourmaline jewels at Frederic Sage, Sloane Street Jewelry, Simon G. and Le Vian. In its 2025 trend forecast, Le Vian highlighted watermelon tourmalines as part of a broader trend for exotic, vividly coloured stones that are the perfect vehicles for displaying your individuality. “Le Vian has a particular fascination with tourmalines,” says Eddie LeVian, CEO at Le Vian. “Le Vian’s collection of watermelon tourmalines has captivated collectors, surpassing expectations despite their natural inclusions. These inclusions, unique birthmarks, add to their individuality and charm.” 

A designer who has ‘The Home of Watermelon Sugar’ in her Instagram bio is Genevieve Schwartz from London. She has a wide selection of minimalistic rings, earrings and pendants with watermelon tourmalines set in simple prong settings, sometimes complimented with a halo of diamonds or additional tourmalines. This streamlined design approach is understandable. When the actual gemstone is so complex and fascinating, you want nothing to take attention away from it. “These unique pieces are ‘one of a kind’ conversation starters,” she says of her ‘sugar’ jewels.

Whether you are drawn to pastel bicolour tourmalines that display a subtle ombré effect as the colours shift from one to the next or prefer intensely hued stones with a clean junction between the two, these natural marvels that intrigue with their colour diversity have, in just ten years, shifted from gemmological curiosity to collector favourite. As huge fans of colour at KaterinaPerez.com, we are delighted they are being appreciated by an ever-growing audience.