Fibertec mineral wool fibers are inorganic synthetic fibers that have been specifically milled and processed to controlled lengths and with predictable diameters and aspect ratios. These mineral fibers are generated from complex mineral silicates having as primary components silicates of calcium, magnesium and aluminum. Fibertec mineral fibers can be surface treated to enhance performance in selected resin systems. urther, because these fibers are additionally characterized by very low loose and tapped bulk densities, they are desirable for low-density reinforced thermoset and thermoplastic systems.