differ in their aluminium content, form a continuous solid solution at elevated temperature. As the amphibole cools, the two end members exsolve to form very thin layers (lamellae).

Hornblende is highly variable in composition, and includes at least five solid solution series: magnesiohornblende-ferrohornblende , tschermakite-ferrotschermakite , edenite-ferroedenite , pargasite-ferropargasite and magnesiohastingstite-hastingsite . In addition, titanium, manganese, or chromium can substitute for some of the cations and oxygen, fluorine,