Minerals and Metals in Ancient India v2.c43.s3.t9.1

v2.c43.s3.t9.1

Actinolite means ‘ray’ in Greek, and is a typical calcium-magnesium-iron (fibrous) amphibole silicate Ca₂ (Mg,Fe)₅ (OH)₂(Si₄O₁₁)₂. Substitution by aluminium in this structure results in hard and intertwining fibres and a family of gem minerals known as Jade. These minerals may have hardness only 6-7, sometimes 5-1/2 in the Moh’s scale and yet, on account of the fibrous structure these are exceptionally tough and difficult to fracture.