Peridotitti

Peridotitti is a rare ultramafic intrusive igneous rock characterized by its high olivine content, typically exceeding 40%. The name "peridotitti" is derived from "peridot," the gem-quality variety of olivine. These rocks are essentially coarse-grained equivalents of peridotite and are often found in specific geological settings. The primary mineral in peridotitti is olivine, which gives the rock its characteristic green color, ranging from yellowish-green to olive green. Other common minerals found in peridotitti include pyroxene (such as enstatite or diopside), spinel, and sometimes minor amounts of chromite or magnetite. The texture of peridotitti is typically phaneritic, meaning its mineral crystals are large enough to be visible to the naked eye, a result of slow cooling deep within the Earth's crust or upper mantle. Peridotitti forms at high temperatures and pressures and is considered a mantle-derived rock. Its occurrence is often associated with ophiolite complexes, which are fragments of oceanic crust and upper mantle that have been tectonically emplaced onto continental crust. Smaller occurrences can also be found in layered mafic intrusions and kimberlites. Due to its mineral composition, peridotitti is generally dense and hard. Its rarity and the presence of valuable minerals like chromite can make it of economic interest, though large-scale extraction is uncommon. Peridotitti plays a role in understanding the composition and processes of the Earth's upper mantle.