Stemcell Science Shop - Olivine Crystals (Peridot)

Olivine is the most abundant mineral in Earth's upper mantle, making up over 50% of the planet's subsurface by volume. These green crystals — gem-quality olivine is known as peridot — form under extreme heat and pressure deep within the Earth and are brought to the surface through volcanic activity and tectonic uplift. Unlike most minerals you'll encounter, olivine didn't originate in the crust: it comes from the layer beneath it, giving you a direct sample of the material that makes up the bulk of our planet.

Most abundant mineral in Earth's upper mantle — over 50% of subsurface volume
Gem-quality olivine is the birthstone peridot (August)
Forms at depths of 40–400 km under extreme heat and pressure
Estimated to hold more water (dissolved) than all of Earth's oceans combined
Each vial contains ~50 g of genuine olivine crystals

MINERALOGY

Olivine is a magnesium iron silicate with the formula (Mg,Fe)₂SiO₄. It crystallizes in the orthorhombic system and typically presents in shades of olive to bottle green, depending on the iron-to-magnesium ratio. Higher magnesium content (forsterite end-member) produces paler, yellower crystals; higher iron content (fayalite end-member) shifts the color toward darker green and brown. Olivine has a Mohs hardness of 6.5–7 and a vitreous luster. It is also found in meteorites — particularly pallasites — and on the surface of Mars and the Moon.

THE WATER CONNECTION

One of olivine's most remarkable properties is its capacity to store water within its crystal structure as hydroxyl (OH⁻) groups. Scientists estimate that the olivine-rich mantle may contain several times more water than Earth's oceans — locked away in solid form hundreds of kilometers underground. This has profound implications for understanding Earth's water cycle, plate tectonics, and volcanic activity.

REAL-WORLD USE

Geologists use olivine as a key indicator mineral for mantle-derived rocks (peridotites, dunites, and kimberlites). Its presence in a rock immediately signals a deep, high-temperature origin. Amateur mineralogists can examine the vitreous luster and characteristic green color with a loupe. Gem cutters facet high-clarity specimens into peridot gemstones. Olivine is also being studied as a carbon sequestration material — it reacts with CO₂ to form stable carbonates, a process called enhanced weathering.

SPECIMEN SPECS