Amphibole

Amphibole

Amphibole is the name of an important group of generally dark-colored rock-forming minerals, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles crystallize into two crystal systems, monoclinic and orthorhombic.

About Amphibole

Amphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles crystallize into two crystal systems, monoclinic and orthorhombic. In chemical composition and general characteristics they are similar to the pyroxenes. The chief differences from pyroxenes are that (i) amphiboles contain essential hydroxyl (OH) or halogen (F, Cl) and (ii) the basic structure is a double chain of tetrahedra (as opposed to the single chain structure of pyroxene). Most apparent, in hand specimens, is that amphiboles form oblique cleavage planes (at around 120 degrees), whereas pyroxenes have cleavage...'

Contributions by Vsmith, ClueBot NG, and Mikenorton.