Rarity in gemstones isn’t the same thing as price. A stone can be genuinely rare and inexpensive if demand is low, or common and expensive if demand is high (this is most of the story behind diamond’s price relative to its actual abundance). What actually makes a stone rare is usually one of three things: it’s found in only one place on Earth, it displays a phenomenon that’s hard to reproduce, or the geological conditions needed to form gem-quality crystals of it are unusually specific.

Rare stones covered on this site

Tanzanite is the clearest example of single-locality rarity among the stones we cover. It’s found in commercial quantities in essentially one place on Earth: the area around Mount Kilimanjaro in Tanzania, where it was discovered in 1967. It’s also the newest addition to any of the standard monthly birthstone lists — added to the December list only in 2002, a fact that says more about how recently it was discovered than about tradition.

Alexandrite is rare for a different reason: it displays a genuine color-change phenomenon, appearing green in daylight and red under incandescent light, caused by how its chromium content interacts with different light sources. It was first found in Russia’s Ural Mountains in the 1830s and named after Tsar Alexander II; the original Russian deposits are now largely exhausted, and while it’s since been found elsewhere (notably Brazil and Sri Lanka), fine color-change material remains scarce and expensive.

Rarer still — stones we haven’t built pages for yet

A few gemstones are rarer than anything currently in our database, and rather than write property pages for them without verifying every figure against a primary source first, we’re naming them honestly here:

  • Painite was listed for decades as one of the rarest gem minerals on Earth after its discovery in Myanmar in the 1950s — for a long stretch, only a small handful of specimens were known to exist worldwide, though more have been found since.
  • Musgravite, discovered in 1967 in the Musgrave Ranges of South Australia, is a member of the same mineral group as taaffeite and remains one of the least commonly cut gemstones in the trade.
  • Taaffeite has an unusual origin story: it was identified in 1945 by gemologist Richard Taaffe from an already cut and polished stone that had been misidentified as spinel, making it the only gem species first discovered from a finished piece of jewelry rather than a rough crystal.
  • Red beryl (sometimes called bixbite) is a beryl variety — the same species as emerald and aquamarine — found in gem quality in only a few locations in Utah, and is frequently cited as rarer than diamond by weight of material found.
  • Grandidierite, named after French explorer Alfred Grandidier and first found in Madagascar, is common enough in cloudy, opaque form but genuinely rare as a transparent, facetable gemstone.

We’ll add proper reference pages for these as we verify their properties against primary gemological sources — the same standard we hold every other page on this site to.