Minerals identify

Know how to recognize them

Chloritoid

Nesosilicates

Chloritoid is a silicate mineral of metamorphic origin. It is an iron alumino, Mg ) 2Al 4Si 2O 10(OH) 4. It occurs as greenish grey to black platy micaceous crystals masses. Its Mohs hardness is 6.5, unusually high for a platy mineral, and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites.

Both monoclinic polytypes

It was first described in 1837 from localities in the Ural Mountains. It was named for its similarity to the chlorite group

Identification

Color of mineral

Grey
Green
Black

Mohs scale ( mineral hardness )

6.5

The streak

Green

Density ( specific gravity )

1.713
1.719
1.723

Luster ( interacts light )

Pearly

Crystal ( diaphaneity )

1Apolytype:tric