Chloritoid is a silicate mineral of metamorphic origin. It is an iron magnesium manganese alumino silicate hydroxide with formula: (Fe,Mg,Mn)₂Al₄Si₂O₁₀(OH)₄. It occurs as greenish grey to black platy micaceous triclinic crystals and foliated masses. The Mohs hardness at 6.5 is unusually high for a platy mineral and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites, schists and marbles. The silicate minerals make up the largest and most important class of rock-forming minerals. ... Metamorphism can be defined as the mineralogical, chemical and crystallographic changes in a solid-state rock, i. ... In crystallography, the triclinic crystal system is one of the 7 lattice point groups. ... Foliation is any penetrative planar fabric present in rocks. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... Phyllite Phyllite is a type of foliated metamorphic rock primarily composed of quartz, sericite mica, and chlorite; the rock represents a gradiation in the degree of metamorphism between slate and mica schist. ... Schist The schists form a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. ... Venus de Milo, front. ...

It was first described in 1837 from localities in the Ural Mountains region of Russia. Map of Ural Mountains The Ural Mountains (Russian: Уральские горы = Урал) also known simply as the Urals and as the Riphean Mountains in Greco-Roman antiquity, is a mountain range that runs roughly north and south through western Russia. ...

References

• Webmineral data
• Mindat