A monoclinic mineral (clinochrysotile), or orthorhombic mineral (orthochrysotile, parachrysotile), (Mg₆(OH)₈Si₄O₁₀) ; serpentine group; forms soft, silky white, yellow, green, or gray flexible fibers as veins in altered ultramafic rocks; the chief asbestos minerals. (Not to be confused with chrysolite.)