Axinite is a borosilicate mineral that comes in a variety of colors and…

Axinite is a borosilicate mineral that comes in a variety of colors and crystal shapes. It’s known for its strong pleochroism, which means it changes color when viewed from different angles. Color: Brown, violet-brown, violet, reddish-purple, red, plum blue, violet-blue, blue, pink, orange, yellow, brownish yellow-green, gray, colorless Crystal structure: Triclinic, with a complex and symmetrical structure Interconnected silicate tetrahedra (SiO₄) with boron-centered polyhedra and metal cations Hardness: Mohs hardness of 6.5–7, but varies with direction Anisotropic hardness, meaning it may vary within a single specimen Transparency: Translucent to transparent Good cleavage, but somewhat brittle Pleochroism: Strong pleochroism, which means it changes color when viewed from different angles Name: From the Greek word axine, which means “axe” Named by French mineralogist Rene Just Haüy in the late 18th century Formation: Forms in low- to medium-grade metamorphic rocks Often associated with contact metamorphism