peridotiitin

Peridotitin is a rare and distinctive mineral that belongs to the sorosilicate group, characterized by its unique chemical composition and vibrant green color. The mineral was first identified in 1962 by mineralogists studying specimens from the Kola Peninsula in Russia. Its name derives from the Greek word *peridot*, meaning "emerald," reflecting its gem-like appearance, though peridotitin is not as widely recognized as other green silicates like peridot or olivine.

Peridotitin has the chemical formula Ca₄(Fe²⁺,Mg)₅(Al,Fe³⁺)₂(Si₂O₇)₂(SiO₄)₂O₂(OH)₂, indicating it contains calcium, iron, magnesium, aluminum, silicon, oxygen, and hydrogen. It crystallizes in the monoclinic system and typically forms small, tabular crystals or granular aggregates. The mineral is often found in metamorphic rocks, particularly those associated with skarn deposits, which are formed by the reaction of hydrothermal fluids with limestone or dolomite.

One of the most notable occurrences of peridotitin is in the Lovozero alkaline massif in the Kola Peninsula, where it was first discovered. Other occurrences have been reported in Greenland, Norway, and the United States, though these are less common. Due to its rarity, peridotitin is not widely collected by mineralogists or gem enthusiasts, and specimens are highly valued by specialists in mineralogy.

The mineral’s physical properties include a hardness of approximately 5.5 to 6 on the Mohs scale, a vitreous to resinous luster, and a pale green to yellowish-green color. Under ultraviolet light, peridotitin may exhibit faint fluorescence, though this is not a consistent feature. Its diagnostic characteristics, such as its chemical composition and crystal habit, help distinguish it from similar minerals like epidote or vesuvianite.

While peridotitin is not commercially significant, its study contributes to the understanding of metamorphic processes and the formation of rare minerals in alkaline and skarn environments. Researchers continue to explore its occurrence in new localities, expanding knowledge of its geological context.