aktinoliit

Aktinoliit is a mineral that belongs to the amphibole group. Its chemical formula is Ca2(Mg,Fe)5Si8O22(OH)2. The name "aktinoliit" comes from the Greek words aktis, meaning "ray," and lithos, meaning "stone," referring to its often acicular or fibrous crystal habit, which can form radiating aggregates. It is a solid solution series between tremolite (Mg-rich) and ferro-actinolite (Fe-rich). The presence of iron in its structure gives it a characteristic green color, ranging from pale green to dark green. Aktinoliit is a common constituent of metamorphic rocks, particularly those formed under low to medium-grade metamorphic conditions, such as greenschists and amphibolites. It can also be found in some igneous rocks. The hardness of aktinoliit on the Mohs scale is typically between 5 and 6. It has a vitreous to silky luster and a specific gravity of around 3.0 to 3.4. While not a primary ore mineral, it can be a component of jadeite-bearing rocks, where it contributes to the overall composition and color. In some cases, fibrous varieties of aktinoliit can be associated with asbestos, though it is not considered as hazardous as other asbestos minerals like chrysotile or amosite.