In archaeology, a projectile point is an object that was hafted and used either as knife or projectile tip or both. Occasionally, projectile points made of worked bone or ivory are found at archaeological sites, but generally the term is reserved for a refined chipped-stone biface. Projectile points fall into two general types: dart points and arrow points. Dart points are defined as those bifaces which were used to tip spears and atlatl darts. Arrow points are smaller and lighter than dart points, and were used to tip arrows. Both dart and arrow points come in a bewildering variety of styles, which vary according to geographic area.