Amphibole

Amphibole, the name of a group of minerals which are essentially silicates of lime and magnesia; but these bases are often partly replaced by alumina, and oxides of iron and manganese. The most important minerals in this group are Tremolite, Actinolite, Nephrite (Jade), and Hornblende. Asbestos and its varieties are forms of Tremolite and Actinolite. Many of these occur as fine hair-like filaments, readily separable from each other (Amiantus, mountain-flax); in other cases, the filaments or fibres are more or less firmly interwoven, giving rise to products which closely resemble the substances after which they are named—mountain-flax, mountain-leather, mountain-cork.