It took 22 years for the Kat Florence Lumina Paraíba tourmaline to reach the auction stage, selling in May 2025 at Bonhams Hong Kong for close to US$500 000 (HK$3.81 million). While Durban-born gem hunter Don Kogen, who unearthed this rare beauty, felt it could have achieved a higher hammer price without uncertainties around import tariffs, it was still a rewarding result.
Don has been doing what the uninformed might compare to Romancing the Stone for most of his life and has sold his fair share of sizeable, valuable gems to the world’s greatest jewellers, including his wife, who gave this one her name – Kat Florence.
Ultimately, the Kat Florence Lumina was sold to a local, who promptly commissioned Kat to design a jewellery piece featuring the stone, a natural trajectory for all involved.
“Wearing a Paraíba tourmaline is like wearing light itself,” says Kat, a quality its new owner will discover in due course. The 181.61-ct, finely cut, flawless Paraíba tourmaline was presented unmounted to reinforce its gemmological significance – a legend in the world of coloured gems with a lineage rooted in discovery, shaped by vision, and perfected by hand.
Top-tier certifications from leading gemmological authorities, including AGL, GRS, Bellerophon, and Gübelin, confirmed its natural, untreated status and Mozambican origin. Gübelin’s 95.4-point rating – a distinction awarded to a small percentage of submissions annually – affirmed its exceptional quality across clarity, colour, and cut.
Thinking back, Don adds, “The stone has history. I remember getting it out of the ground in Mavuco, Nampula, about four hours away from the Mozambican site where Paraíbas were discovered in 2003. That wasn’t really announced until 2005, but I remember we were there looking for aquamarine, different tourmalines, and there it was – this big rock. It was like a freak of nature.”
The original rough weighed 830 carats. From the outset, Don recognised its potential. Most Paraíbas are purple or reddish, or have a different overtone; they are seldom naturally blue. “We came across this purple material, which I’d seen before in Nigeria. And I thought, oh my goodness, does this have copper? That’s the only differentiator between Paraíba and normal tourmaline – the metallic element within the crystal structure – and those with copper content are only found in Brazil, Nigeria, and Mozambique. It’s what defines that neon effect, to give you that pop.”
While originally discovered in Brazil in the 1980s, African deposits have since yielded larger, often cleaner specimens. The Lumina is considered the finest of these African-origin stones to enter the auction circuit. Cutting it was tricky, but one relished by Don, who reserves the right to trim stones of his choosing before handing them over to the elite cutting team at the Kat Florence Spa, as they call it – if that is their destiny. He loves it and tries to keep the stone as weighty as possible. However, Kat, as a designer, is less concerned about the weight and more about the look. The initial cut of the Lumina, though large at 315 carats, lacked the brilliance that defines the very best Paraíba material. The challenge lay in the stone’s structure, which created optical flatness, a phenomenon known as “windowing” that diminishes light performance in large tourmalines. “It’s like a fish-eye, and Kat was having none of it,” he says.
Don can’t help getting excited about his discoveries, but he has learned to accept his wife’s uncompromising approach to the final cut, even if it is at the expense of weight. Kat elaborates: “This is literally our lives. I see the stone, and I see the potential if we cut it. For me, it’s like seeing something that you know you could carve and shape differently, and it would be the most beautiful thing you’ve ever seen in the world.”
“We’re so different, but we have, I would say, the same values.” Acknowledging Don’s skill, she says, “I am amazed at how you read rough. I think it’s like a superpower. So, I think it’s about respecting what you can do, and then what I do. And you would never say anything about design.”
Proving her point, the Kat Florence Lumina marries volume with brilliance, a rare quality in Paraíba material of this scale. The stone is balanced, flawless, and visually saturated, exhibiting the intense bluish-green hue characteristic of the finest copper-bearing tourmalines.
Kat Florence views their collaboration as ideal. “It’s honestly a match made in heaven because Don finds the rarest stones, and I love working with those. And what fascinates me is the cutting process. I love that each family of stone must be cut completely differently from one another. I find the refraction of light and what colour can occur more interesting.”
She reflects on what drew her into the field. “I had done my master’s in education and had a background in biopsychology. I was running an art-based school, teaching concepts like reflection and refraction to children, and just naturally fell into this. I was in Bangkok, stumbled across a stonecutter friend, and just started experimenting.”
Kat’s first piece was an emerald, and she “fell in love with it. I had only ever wanted to create one-off pieces, but I never dreamed it would become something big. It’s kind of incredible what came of it. I feel blessed and honoured that I get to decide what that stone is going to look like, probably for the rest of eternity, right?”
There’s just one rule when you commission a Kat Florence piece. Don explains: “Nobody can have an opinion. Kat needs a free hand to re-engineer it. What defines a Kat Florence piece of jewellery is Kat Florence. If you want to transform this gem into a piece of art, that’s what she does. Let it go. Close your eyes. Do what I do all the time. Enjoy the ride.”
