Gem Minerals
Olivine
What it is
The gem variety of olivine is peridot, one of the few gemstones that comes in only one color: green. Olivine is a major component of Earth's upper mantle and is among the first minerals to crystallize from basaltic magma.
How it forms
Crystallizes at very high temperatures (1200–1900°C) directly from the mantle or from basaltic magma. Peridot gem crystals form in deep mantle rocks that are brought to the surface by volcanic eruptions.
(Mg,Fe)₂SiO₄
