Crust vs. Mantle: Where Gemstones Actually Come From
Every gemstone's story
begins long before the bench.
It begins with where
the Earth made it.
Two Very Different Neighborhoods
The crust —
thin. cool. where we live.
The mantle —
2,900 kilometers deep.
Hotter. Denser. Under far greater pressure.
Most familiar gems —
emerald, ruby, sapphire, tourmaline —
form in the crust.
Diamond and Peridot: Mantle Natives
Diamond crystallizes
150 to 200 kilometers down.
Conditions that simply
don't exist above.
Peridot, too,
born in the upper mantle.
How Mantle Gems Reach Us
The mantle isn't reachable.
So gems need an elevator —
violent, fast.
Kimberlite pipes.
Lamproite pipes.
Erupting before the stone
has time to change back.
Why This Matters to Buyers
Crust-formed gems —
more variety. More sensitivity to treatment.
Mantle-formed gems —
simpler chemistry. Rarer access.
Next time you set
a diamond beside an emerald —
one traveled from 180 kilometers down.
One formed close to where you stand.
Two journeys.
One box.
