Actinolite

This specimen is composed predominantly of actinolite, a green amphibole mineral that forms during regional or contact metamorphism of mafic and ultramafic rocks. The characteristic green colour arises from iron and magnesium within the crystal structure, while the texture ranges from fine-grained and massive to fibrous or bladed, as seen in this example. For beginners, actinolite can be recognised by its green hue and tough, sometimes splintery appearance. For students and researchers, it is an important index mineral indicating metamorphic conditions typically associated with the greenschist to amphibolite facies, reflecting moderate temperatures and pressures during mountain-building processes.