Clinohumite - Encyclopedia

    Class : Silicates
    Subclass : Nesosilicates
    Crystal system : Monoclinic
    Chemistry : Mg₉(SiO₄)₄(F,OH)₂
    Rarity : Common

Clinohumite belongs to the humite group, which also includes chondrodite and humite. It is a mineral typical of limestones and dolomites affected by contact metamorphism caused by plutonic and alkaline rocks which transformed them into cipolins or marbles, with the accompanying formation of skarns. As with chondrodite, the genesis of clinohumite also requires significant metasomatism (fluorine contribution). Clinohumite is also observed, like chondrodite, in blocks of metamorphosed limestone rejected by Italian volcanoes (beautiful, perfectly formed crystals at Vesuvius and Mount Somma, near Naples). Its name is related to its monoclinic structure and its chemical similarity with humite. Clinohumite crystals form rounded grains with a cracked appearance, more rarely isometric or tabular individuals, rich in faces, with shapes reminiscent of olivine, generally not exceeding 1 cm. Twins and aggregates are common. The color ranges from yellow-orange to red-brown, even brown. Gem crystals are commonly cut for jewelry.

Main photo : Clinohumite from Kukh-i-Lal, Pyandzh River Valley, Gorno-Badakhshan, Tajikistan © Oleg Lopatkin

A twin is known on {100}, simple or lamellar.

No fake identified for this mineral species.