MaterialInvisibleMetalness Property

Value between 0 and 1. If 0, the reflected specular light is multiplied with the material diffuse color. This is often the case for metals, e.g. gold. If 1, the reflected specular light has the same color as the incident light (thus as if it is reflected at a white surface). This is often the case for plastics.

public double Metalness { get; }