Larimar, with its captivating blue color, which can vary from light blue to pale green or intense sky blue, has a hardness of 4.5 to 5 on the Mohs hardness scale. This enthralling gemstone has a fibrous-radiated structure and is opaque or semi-translucent with silky, sub-vitreous luster. It also has a specific gravity of about 2.81, with an average refractive index between 1.599 and 1.628. Larimar has an uneven fracture with perfect cleavage on and (crystal form) but no cleavage when compact.