A corner trim material that is made of a material that will bond with current industry mastics such as all purpose joint compounds, resists impact, resists abrasion, and readily accepts common coatings such as drywall mud, texture and paints. The surface of this material generally does not need to be covered by any secondary fiber based material such as paper to improve bonding or coating on the inside or outside. The material generally consists of a polymer mixed with a fibrous material like pulp or glass fiber. A corner trim piece can be directly extruded from the mix. The corner trim piece can have a center hinge, can be bullnose, and the flanges can optionally have holes or optionally be coated with adhesive.