Definition of: amphibole

(am′fə·bōl) noun Mineral.
Any of a class of variously colored hydrous silicates, consisting chiefly of calcium, magnesium, iron, aluminum, and sodium; tremolite, actinolite, asbestos, and hornblende are important varieties. [<F <L amphibolus ambiguous <Gk. amphibolos <amphiballein to throw around, to doubt <amphi- around + ballein throw]