Peridot falls out of the sky and Cleopatra's emeralds probably weren't emeralds

My birthstone is peridot and I've been mildly annoyed about that my whole life because it's the yellowish-green one nobody's impressed by. Then I read about it properly last winter and now I'm insufferable in the other direction.

Peridot is gem-quality olivine, one of the most common minerals in Earth's mantle. Most of what you see came up through volcanic activity from deep down — it's not a crust mineral that formed near where we live, it's a piece of the layer underneath.

There are green sand beaches in Hawaii made almost entirely of olivine crystals weathered out of lava. An entire beach of it.

But the part that got me: peridot is also found in meteorites. Specifically pallasites — a rare class of stony-iron meteorite where olivine crystals sit suspended in a nickel-iron matrix, thought to come from the boundary between the core and mantle of a shattered early planetesimal. People have cut and faceted gem peridot out of meteorites. You can buy a stone that formed inside a destroyed proto-planet and fell here.

And then the history. The main ancient source was Zabargad, a small island in the Red Sea, mined for thousands of years and periodically lost — the location was forgotten and rediscovered more than once. There's a decent argument in the literature that a lot of what got called "emerald" in the ancient Mediterranean, including Cleopatra's famous ones, was actually peridot from that island. Same green, wrong mineral, and nobody had the analytical tools to know the difference.

So: my boring birthstone comes from the mantle, sometimes from space, was mined on an island people kept losing, and spent centuries being mistaken for something more prestigious.

I bought myself a decent one in February. Not a meteorite one, those are absurd money. Just a normal terrestrial piece, faceted, about the size of a lentil.

I look at it more than I expected to. Mostly I think about the beach.