Bi-color tourmaline cut by John Dyer
Parti Color Sapphire cut by John Dyer & Co.

Bicolor and parti-color gems, with their play of multiple hues, are a popular choice for stunning statement pieces and alternative engagement rings.

Having a single stone that sports two or more hues is nothing new. But for the most part, such gems have been the cloistered darlings of mineral collectors. Today, they are finding popularity in the mainstream thanks to a growing appreciation for exotic stones.

Several gem-mineral species naturally produce either bicolored stones — which specifically show two colors — or parti-colored ones, which can boast more. Quartz varieties (amethyst, ametrine, citrine), tourmaline, sapphire, topaz, tanzanite and — rarely — kunzite are all available in parti-color form.

Where to find them
The origins of these stones are as exotic as their appearance. For tourmaline, suppliers scour deposits in Afghanistan, Brazil, East Africa, Nigeria, Mozambique, Madagascar and the US. Bolivian miners first surprised the world centuries ago by bringing out ametrine, a bicolored quartz variety in shades of purple and yellow. To this day, nearly all commercial production of ametrine hails from Bolivia.

Parti-colored sapphire can be found wherever sapphire is mined, including India, Ceylon (Sri Lanka), Burma (Myanmar), Australia, Brazil, Thailand and Vietnam. But Montana sapphire in particular is renowned for its dramatic parti-color varieties. Parti-color topaz is mined worldwide, with Brazil and, more recently, Zimbabwe being large-scale producers. Gemstone dealers often develop an affection for certain material due to its appeal among fans of distinctive stones.

I started working with parti-colored gemstones around 1997, mostly with tourmaline and Montana sapphire,” recalls wholesaler Todd English, owner of Rhode Island’s Integrity Gem. “I love all the multicolored stones, but I’m personally fond of parti-sapphires from Montana, Kenya and Madagascar.

Bi-color tourmaline cut by John Dyer
Bi-color tourmaline Zig Zag™ cut by John Dyer & Co.

Selling the magic
Retailers who know how to present these stones to consumers will generate the most interest, since shoppers often encounter parti-colored gemstones for the first time in a retail setting.

They make wonderful rings, earrings, or pendants,” notes Jo Deng, owner of Florida-based jeweler Aurora Designers. Deng is known for featuring unusual gems in her original jewelry, and these showy multi-hued stones beg to be admired.

To best explain parti-colored  gemstones, a store should first have a selection on hand and let the client see the beauty and feel the excitement of a truly unique and rare gemstone from an exotic place,” English advises. “Explain it in simple terms and let the romance of owning a beautiful one-of-a-kind [specimen] guide the client experience.

Gemstone wholesaler Geoffrey Watt, owner of Mayer and Watt in Kentucky, affirms that the storytelling aspect of the stones’ origins holds jewelry collectors spellbound. “I usually discuss how the change in this material happened,” Watt says, explaining that several occurrences during the growth phase converge to create that hypnotic parti-color result. As crystals form underground, the chemical content of the solution surrounding them can change — and when it does, so does its color. This distribution of trace minerals can create a variety of shades, and sometimes, more than one will share space in the same crystal. 

Where this material was growing, one part of the stone experienced a measure of change,” says Watt. “Whether slight, minor, excessive, or shocking, [something] happened while it was growing for half the material to change its color.” 

Pamela Froman Fine Jewelry 18-karat yellow gold stylized Maltese Cross pendant featuring a Bolivian John Dyer Starbrite-cut 9.85-carat ametrine, with diamonds.
Pamela Froman Fine Jewelry 18-karat yellow gold stylized Maltese Cross pendant featuring a Bolivian John Dyer Starbrite-cut 9.85-carat ametrine, with diamonds.

The cutting edge
The cut is an important part of showcasing parti-color stones. “The best cut usually depends on the shape of the rough and the color zoning inside the stone,” observes Deng. “For example, bicolor tourmalines are often cut into rectangular shapes with facets that are parallel to the stone’s pavilion, because tourmaline rough usually comes in [elongated pencil] shapes. However, bicolor or parti-color sapphires can be seen in any shape or cut style.” Gemstone artist John Dyer of John Dyer Gems in Minnesota has lent his lapidary prowess to a wide array of colored stones for decades, so it’s no surprise that he’s also an expert in parti-color specimens.

In traditional flat faceting, if you want a distinct bicolor effect, then an emerald cut, step cut or other cutting style with a pronounced ‘keel’ instead of having all the facets coming to a point in a brilliant style will keep the colors more separate,” he explains.

That said, he continues, “parti-color sapphires often have unusual color zones and can’t be cut into a straight bicolor like a tourmaline or ametrine can. Clients often like brilliant-style cuts that flash different shades of color as the stone moves instead of having a distinct bicolor.

Some advanced cutting styles that Dyer has created make it possible to cut materials with a definite bicolor into shapes that don’t have a keel (like rounds and ovals) while retaining that distinctive double hue. He points to his proprietary StarBrite and Dreamscape cuts, which use “techniques that few cutters are able to execute, but present another lovely option when you want a bicolor other than a standard rectangular shape.

Parti-color Australian sapphire in John Dyer's trademarked ZigZag cut.
Parti-color Australian sapphire ZigZag™ cut By John Dyer Gems.

Breaking into bridal
Multi-hued stones have become the muse of creative jewelry artists, Dyer says, and couture designers are helping to fuel their upsurge in popularity. “Many designers use parti-color stones now. Among my clients, at least, it’s the rare ones who don’t use them. Designer Pamela Froman of Pamela Froman Fine Jewelry has a special love for bicolors of all kinds. Goldsmith Buddy Austin of Third Eye Assembly, Portland, has done a number of wedding and other rings with our parti-color sapphires.

Dyer understands the appeal; the multitude of shades is the first thing people notice about these gems, “and this causes people to pause and look again.

Also playing into their salability is the consumer desire for something not everyone else has, he believes. The alternative bridal market — for clients who don’t want a diamond — is a case in point. “Engagement rings are very popular with parti-color stones,” he says. “Larger ametrine is super popular, and clients use it in pendants or larger special-occasion rings.”

Dyer recognizes an additional message in using parti-color stones for bridal jewels. “I believe one reason that parti-color material is especially attractive to the bridal market is the whole idea of two people becoming one in marriage, something symbolized during the ceremony. What better way to symbolize this new union than a gem that blends two colors into a single stone?

Ametrine necklace designed and executed by Jeanne and Don Cassanova
Ametrine necklace designed and executed by Jeanne and Don Cassanova

123.49cts Dreamscape™ Ametrine pair from John Dyer Gems. Accent stones from other sources

Article written by Diana Jarrett for

Bicolor gemstones for sale, buy precison cut gemstones in our online catalog
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