Peridot: a gem that sometimes falls from the sky

Peridot is the gem quality form of olivine, a mineral that forms deep in the earth's mantle rather than the crust, which is why peridot deposits are often associated with volcanic activity that brought mantle material up quickly. Genuinely notable fact for this audience, olivine is also the mineral that makes up the crystals found inside pallasite meteorites, meaning peridot and pallasite gem material are essentially the same mineral, one sourced from earth's mantle and the other from the interior of a shattered asteroid. Hardness runs about 6.5 to 7. Peridot always shows some color, unlike most gems it does not occur colorless, and the color comes from iron that is a fundamental part of its chemical structure rather than a trace impurity.