Ethically Sourced Gemstones: Buying Tanzanite and Tsavorite from East Africa’s Finest Mines

Across the hills of Kenya and Tanzania, two gemstones capture the continent’s natural brilliance and enduring mystique: Tanzanite and Tsavorite. Both discovered within a few years of each other in the late 1960s and early 1970s, these extraordinary stones have become the cornerstones of what many collectors now call a particularly notable example of how rare gemstones continue to attract interest from collectors.

At the center of this story stands The Rare Gemstone Company, a Nairobi-based firm that has spent five decades transforming raw stones from East Africa’s earth into heirloom treasures—while pioneering a new era of gemstone purchases rooted in transparency, sustainability, and traceable provenance.From Coffee Fields to Colored Fire

The company’s origins trace back to 1974, when Kenyan coffee farmer Basil Zagoritis noticed his workers unearthing glittering stones in the fields. A chance encounter on a London flight with an American geologist revealed that the “pebbles” were fine sapphires—and a new career was born.

Today, his son Antony Zagoritis leads the firm, blending his background in business and gemology to guide a vertically integrated, mine-to-market gemstone enterprise. “We decided early on to focus on the top one percent of what we find,” he explains. “Our philosophy is simple—integrity in sourcing, precision in cutting, and beauty that lasts for generations.”

Every stone in their collection—from loose gemstones to fully finished gemstone jewelry—is Gemologist Selected, graded by GIA Gemologists and accompanied by professional gemological reports.Tanzanite: A One-Generation Gem

The story of Tanzanite begins in the foothills of Mount Kilimanjaro, where a lightning-sparked bushfire in northern Tanzania exposed brilliant blue-violet crystals. When samples reached Harry Platt, then president of Tiffany & Co., he famously declared them “the most exciting gemstone discovery in two thousand years.”

All known deposits of Tanzanite are confined to a few square miles, making it one of the rarest faceted gemstones on Earth. Less than one percent of mined material displays the deep indigo saturation prized by collectors.“When collectors talk about Tanzanite, they’re not just buying jewelry,” Zagoritis said in a recent LocalLeader.TV interview. “They’re preserving a geological moment that will never happen again.”

With a Mohs scale hardness of approximately 6.5, Tanzanite is best suited for necklaces, earrings, and special-occasion rings. Its unique refractive index gives it remarkable pleochroism—showing flashes of blue, violet, and burgundy from different angles—making fine Tanzanite Jewelry both mesmerizing and instantly recognizable.Tsavorite: Africa’s Emerald

If Tanzanite evokes twilight, Tsavorite Garnet burns with the vivid green of a tropical forest. Discovered in 1967 near Kenya’s Tsavo National Park, this brilliant variety of Grossular Garnet rivals Emerald in color and sparkle, while boasting superior durability and clarity.

“Tsavorite is Africa’s Emerald,” Zagoritis says. “It’s over a billion years old, rarer than Tanzanite once you pass two carats, and one of the purest green gemstones ever discovered.”

On the Mohs scale, Tsavorite registers at a sturdy 7 to 7.5, making it ideal for everyday wear. Its high refractive index—greater than that of emerald—gives it a crisp, internal brilliance that has made it a favorite among jewelry designers seeking ethically sourced green gems. The company recently cut a flawless nine-carat stone. For collectors seeking loose Tsavorite Garnets or custom Tsavorite Jewelry, The Rare Gemstone Company offers one of the most curated selections available, each piece sourced with full provenance.

Color, Craft, and Value

In the world of colored stones, color is king. Roughly 80 percent of a gemstone’s value is determined by hue and saturation, with clarity and carat weight following close behind.

For cutters at The Rare Gemstone Company, every decision aims to maximize a gem’s natural color rather than follow the rigid symmetry prized in diamonds. Each gem is studied for orientation, tone, and brilliance before it’s transformed into a precision-cut faceted gemstone.

This artistry, combined with the company’s full-service design studio and in-house goldsmithing, has made Nairobi an emerging center for luxury gemstone jewelry and mine-to-market gemstones with verified provenance.Provenance: The Future of Ethical Gemstone Sales

Long before blockchain became a buzzword, The Rare Gemstone Company was developing its own digital provenance system to trace each gem from mine to market.

Through a secure mobile app, artisanal miners photograph rough stones at the point of discovery. Each image is timestamped and uploaded to a secure ledger. As the gem moves through cutting, polishing, and finishing, each step is logged. Upon completion, the stone receives a laser-inscribed report number that links directly to its record, certifying it as a Certified Gemstone.

For buyers, that means verifiable authenticity. “It’s transparency in action,” Zagoritis said in the recent gemstone podcast interview. “When someone buys a Tanzanite or Tsavorite from us, they can see the mine it came from, the hands that cut it, and the artistry that brought it to life.”Exploring Color: From Paraiba to Tsavorite

The company’s portfolio extends beyond Tanzanite and Tsavorite to include rare gems like Paraiba Tourmaline and Pink Tourmaline, both coveted for their neon hues and rarity. As with these, supply scarcity drives long-term appreciation—proof that color and provenance often outperform carat weight alone as value drivers.

Historically, the value of certain gemstones—such as Paraiba Tourmaline—has shifted as availability changed. When Brazilian deposits diminished, the stone became more sought-after by collectors. “Nature doesn’t issue more stock,” Zagoritis notes. “Once it’s gone, it’s gone.”

Building Communities

The Rare Gemstone Company’s approach to sustainable gemstone practices extends far beyond documentation. Each sale channels royalties back to mining communities, funding schools, clean water projects, and local development in rural Kenya and Tanzania.

“One discovery can change a family’s future,” Zagoritis says. “We want that success to ripple through generations.”For those who want to make gemstone purchases aligned with social responsibility, this represents the next generation, where financial value and human impact coexist beautifully.

From Nairobi to the World

What began as a small Kenyan export operation has become a global luxury brand. Many first encounter the company while on safari and leave with a tangible piece of Africa’s story.

That story will soon reach a wider audience through a documentary produced by Empowered, airing on public television for a year, and also major U.S. networks including CNN and Discovery. The film highlights the artistry and ethics behind mine-to-market gemstones and the cultural heritage of East Africa’s gem industry.

Holding a Piece of Earth’s Story

For Zagoritis, each gemstone is both artwork and artifact—a fragment of deep time rendered in light.“When you hold a Tanzanite or Tsavorite, you’re touching something that began forming hundreds of millions of years ago,” he says. “It’s not just beauty you’re investing in—it’s history, connection, and the promise of doing business the right way.”

With its focus on artistry, clear provenance, and ethical sourcing practices, The Rare Gemstone Company has established itself as a notable name in responsibly sourced rare gemstones—ensuring that Africa’s treasures, from Tanzanite and Tsavorite to Tourmaline, continue to inspire collectors and GIA-certified gem enthusiasts for generations to come.

Explore the collection at The Rare Gemstone Company.

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