Peridotite and Serpentinite

**Petrology:** Olivine, pyroxene, garnet and chromite are rock-forming minerals of peridotite. Due to activity of hydrothermal fluids under metamorphic conditions (e.g., Variscan orogeny approx. 340 million years ago) peridotite is often altered to serpentinite. The processes are characterized by a creation of the new minerals of serpentine group.

**Genesis:** Peridotite is the dominant rock-type of the Earth's upper mantle, which is formed at high pressure and temperatures (up to 1300 °C) at least 70 kilometers below the Earth’s surface.

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stone