Andalusite

Color: strongly pleochroic, reddish brown, pink / yellowish green Hardness: 7 - 7.5 Refractive index: 1.63 - 1.65 Density: 3.13 - 3.21 Chemical composition: Al2SiO5 Crystal structure: orthorhombic Lustre: vitreous, greasy  Origins: Spain, Brazil, USA, Sri Lanka, Burma. Discovered in Andalusia (Spain), the andalusite stone is relatively rare, with big crystals over 10 ct. especially rare. Due to its remarkable pleochroism effect, the stone is highly valued by collectors. To invest in Andalusite: www.gemsinvestors.com