Brazil Ran Dry. The Glow Didn't.

The first half closes quietly. The New York sales are settled, Gemfields' spring auctions are done, and the scaled-back June ruby auction has yet to post a result. On a week with no fresh hammer, it is worth turning to the stone that quietly sits at the very top of the Carat Brief Index and almost never gets explained: Paraíba tourmaline, the index's most expensive line at $310,000 per carat.

It is a useful stone to study right now, because its price rests on the same foundation that carried Kashmir up on June 9. The original source is effectively mined out. What is left is finite, the demand is global, and the per carat number is set by color and origin, not by size. Paraíba is, in other words, a closed-supply story wearing a neon coat.

→ The June ruby result is still pending. Gemfields ran a deliberately smaller June auction of selected grades, citing lower Montepuez production, liquidity concerns and subdued Chinese demand, and said a fuller update would follow. As of this edition, no figure has been published. We hold the ruby row until it does (Gemfields; Sharecast).

→ Sapphire was the half's only index mover. The June 9 Christie's result lifted fine Kashmir to about $138,700 per carat, above April's $130,400. Every other index row held through H1, a reminder that colored stones reprice on events, not on calendars (Christie's; National Jeweler).

→ Paraíba's source map has shifted. Brazil's original deposits, the basis for the gem's prestige, are largely depleted. Mozambique is now the primary producing source, with Nigeria a minor third. The name has outlived its mine (IGS; GIA; AGTA).

The index tracks the 8 reference stones every week. Each row holds until a new dated transaction moves it. No realized colored stone print has landed since June 9, so the index is unchanged. This week's focus is the tourmaline row.

Auction prices realized, not retail. Sources: Christie's, Gemfields, Bonhams, GemGuide, Pala International.

Notable this week: the tourmaline row is the quiet giant of the index. At $310,000 per carat it sits above fine Kashmir sapphire, above alexandrite, above everything except the rarest blue diamonds. Yet it draws a fraction of the attention. That gap between price and profile is exactly where mispricing lives.

In 1989, a Brazilian miner named Heitor Dimas Barbosa, who had dug for years in the hills of Paraíba state convinced something extraordinary was buried there, finally hit a vein of tourmaline in a color no one had seen. Electric blue and green, lit as if from inside. The glow came from copper, an element found in no other tourmaline, working alongside manganese. The trade had a new gem, and within a few years prices that started near $200 per carat at the 1990 Tucson show had passed $20,000 (IGS; Gemological sources).

The name outgrew the place. Copper-bearing tourmaline turned up in Nigeria around 2000 and in Mozambique soon after. The colors overlapped enough that the labs, led by AGTA and the LMHC framework, made a decision that still shapes pricing today: Paraíba became a variety name for any copper-bearing tourmaline, not a strict origin. Origin is then determined separately, and the GIA's chemical fingerprinting can now separate Brazilian, Mozambican and Nigerian material analytically. That distinction is not academic. It is one of the largest single inputs into the price.

Where it comes from now, and what that costs. Brazil gave the gem its name and still commands the steepest premium, particularly for vivid "old mine" Batalha material. But the Brazilian deposits are largely worked out, and what little comes up tends to be small and included. Mozambique is now the primary source, producing larger and often cleaner stones. Nigeria is a smaller, generally lighter third.

Trade and lab-guide ranges (IGS, Bonhams, dealer guides). Origin, color saturation and documentation drive value far more than weight.

Why it sits at $310,000. The index reference is a 13.54 carat Brazilian Paraíba in a Tiffany triangular cut, sold at Christie's. A stone like that gathers three premiums at once: Brazilian origin, vivid neon saturation, and a size that is almost impossible to find in Brazilian rough, which the trade describes as coming in pencil-thin veins. The market estimates that for every 10,000 diamonds mined, only one carat of Paraíba surfaces. When a stone clears all three bars, the per carat number stops behaving like a tourmaline and starts behaving like a closed-mine sapphire.

The lesson, and it is the recurring one. Paraíba prices the same way Kashmir does, and the same way the two blue diamonds did on June 9. Saturation and origin set the number. Size only multiplies whatever they decided. A vivid, documented, Brazilian one carat beats a pale three carat every time.

1. Brazil is the new Kashmir, structurally. Once a primary source is mined out, its existing stones become a fixed and shrinking pool. Brazilian Paraíba now behaves like Kashmir sapphire: no resupply, a global buyer base, and a premium that compounds as the material disperses into private hands. Treat documented Brazilian stones as the scarce end of the curve.

2. The lab report is a pricing document, not a formality. Because Paraíba is a variety name, origin is established by a lab, and Brazilian origin can carry a multiple over identical-looking Mozambique material. Never buy fine Paraíba described as Brazilian without a report from GIA, SSEF or a peer lab stating it.

3. Treatment disclosure separates the tiers. Heat is standard and accepted in Paraíba when disclosed. Untreated neon stones are genuinely rare and command a premium over treated ones of the same color. The word to look for on the report is the treatment line, and its absence is not the same as "none."

→ The June ruby result. Still pending. Sell-through and bidder count over the headline average. It is the next event that moves the index.

→ Geneva, November. The autumn Magnificent Jewels sales typically bring at least one important Paraíba. The next public test of the $310,000 reference will come there.

→ Mozambique Paraíba output. As the swing source, Mozambique's production now sets the floor for the broader Paraíba market, the way Montepuez does for ruby. Watch supply out of the country, not just the trophy lots.

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Find a Paraíba you like online, from a dealer or an auction lot, and check one thing: does the listing name a lab-confirmed origin, or just call it "Paraíba"? The answer is often the difference between a Brazilian stone and a Mozambique one wearing the same name, and frequently a difference of several times the price.

— Carat Brief

Carat Brief is editorial. Nothing here is investment, legal, or tax advice. Gemstones are illiquid and require certified verification before purchase. Work with credentialed labs: GIA, AGL, SSEF, Gübelin, Lotus Gemology.

Sources: International Gem Society; GIA; AGTA; Bonhams; Christie's; Gemfields; Sharecast. Per-carat ranges are trade benchmarks and vary by color, clarity, origin and documentation.