Every other stone in this index comes from more than one place. Sapphire from Kashmir, Ceylon, Madagascar. Ruby from Mogok and Montepuez. Emerald from Colombia and Zambia.

The stone we're focused on this week comes from two small patches of East Africa, full stop. It sits at the bottom of the index at $8,000 a carat, and it happens to be rarer at the source than the gem it's constantly compared to.

Key Takeaways

→ A quiet auction calendar. No new realized colored-stone print has landed since our last edition. Gemfields' next Mixed-Quality ruby auction remains scheduled for October 2026, following June's Trade Select sale ($23.1M, 93.2% of carats sold, avg $66.30/ct). That's still the next result that can move the ruby row. (Gemfields; Investegate)

→ Christie's keeps calling the shift structural. The house's first Luxury Trends Report described 2025 colored gemstone demand as “surging,” with Asia and the Middle East as the key drivers, and forecast an even larger increase for 2026. (Rapaport, via Christie's report)

→ Green is having a moment beyond emerald. Trade coverage this year keeps circling back to alexandrite and Paraiba tourmaline as the growth names in colored stones — and increasingly, tsavorite garnet gets mentioned in the same breath. (National Jeweler; trade guides)

The index tracks 8 reference stones, weekly. Each row holds until a new dated transaction moves it. No realized print has landed since our last edition, so every row is unchanged.

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

Notable this week: we've adjusted the ruby row's reference to June's Trade Select average ($66.30/ct) rather than February's Mixed-Quality print ($279/ct). Gemfields itself flags that the two formats aren't directly comparable, different baskets, different grade mixes. The honest read is that the ruby row is in a holding pattern until October's Mixed-Quality sale gives us a like-for-like number again.

Green, but not the one you're thinking of. Tsavorite is the vivid green variety of grossular garnet, colored by trace vanadium and chromium. Discovered in 1967 by British geologist Campbell Bridges, first in Tanzania and then, after the deposit was nationalized, in Kenya near Tsavo National Park, the gem it was eventually named after. It is a genuinely recent addition to the fine gem trade, a stone with a founding story inside living memory, unlike almost everything else in this index.

The rarity claim, stress-tested. Jewelry retailers love to cite a specific multiple for how much rarer tsavorite is than emerald, four times, two hundred times, a thousand times, depending which site you land on. None of those numbers trace back to verifiable production data, and we're not going to repeat one as fact. What does hold up: emerald is mined commercially across a dozen countries. Tsavorite, at gem quality, comes from two small footprints in East Africa, Kenya's Taita-Tsavo area and Tanzania's Arusha/Manyara region, with a minor Madagascar occurrence. Fewer sources, smaller deposits, a far shorter supply chain. That's the defensible version of “rarer,” and it doesn't need a made-up multiplier to matter.

Trade ranges for vivid, eye-clean material. Pale or heavily included stones trade at a fraction of these figures.

The part that actually beats emerald. Tsavorite is almost never treated. No oil, no resin, no clarity enhancement, a rarity in a market where the norm for emerald is the opposite. It also carries a higher refractive index than emerald, so a clean stone shows more brilliance for the same size. What it doesn't carry is emerald's five thousand years of cultural weight, and that gap in recognition, not scarcity, is most of why it still trades at a discount.

Don't confuse it with demantoid. Demantoid is a different species entirely, an andradite garnet, mostly Russian, prized for dispersion higher than diamond's and for horsetail inclusions collectors specifically seek out. Top demantoid can run $10,000–$25,000/ct, above tsavorite's ceiling. Same family, different gem, different buyer.

1. Ignore the multiplier, trust the geography. “200 times rarer than emerald” is marketing, not data. “Mined commercially in two East African districts, full stop” is the fact that actually supports a premium.

2. Untreated is the baseline, not the upsell. With tsavorite, assume no treatment and verify only if a seller claims otherwise. That's the inverse of how you should approach emerald, ruby, or sapphire, and it's worth remembering which stones flip the default.

3. The ruby row just lost its clean comparable. Gemfields' new Trade Select format means February's $279/ct and June's $66.30/ct aren't measuring the same thing. Treat the row as paused until October's Mixed-Quality sale restores a like-for-like print.

→ October's Gemfields Mixed-Quality ruby auction. The next figure that can genuinely move the ruby row, on a comparable basis to February's print.

→ Tsavorite's profile in trade press. It's increasingly named alongside alexandrite and Paraiba as a 2026 growth story. Watch whether that turns into auction-house attention, the way it did for spinel.

→ Geneva, November. The autumn Magnificent Jewels sales are the next major test of demand across the board, sapphire, emerald, ruby, and the smaller stones riding their coattails.

Next time someone tells you a stone is “200 times rarer” than another, ask them where the number comes from. Almost nobody can answer, because almost nobody is measuring production at that resolution.

The better question, for tsavorite or anything else: how many places on earth actually produce this, at gem quality, today. That number is usually small enough to make the point without any invented multiplier attached to it.

— 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: Gemfields Group auction results, June 2026; Investegate; Rapaport; Christie's Luxury Trends Report; National Jeweler; Sosna Gems, Armonia Gems, and RubyGlint 2026 tsavorite and garnet price guides. Per-carat ranges are trade benchmarks and vary by color, clarity, size and documentation.