Igneous or metamorphic rock composed largely or dominantly of amphibole minerals.
For igneous rocks, the term hornblendite is usually used and is more restrictive; hornblende is the most common amphibole. Metamorphic amphibolites are more widespread and variable than igneous ones. Typically, they are medium-to coarse-grained and are composed of hornblende and plagioclase . Basic igneous rocks such as basalts and gabbros (see acid and basic rocks ) can be the parent rocks of amphibolite.