Since ore (called country rock) is generally large and thick, it is not suitable for making small stone tools, therefore, flakes were often made first then made into stone tools (mainly chipped stone tools).
原石（これを母岩という）は一般に大きくて厚みがあるので小形の石器をつくるのには不向きであり、剥片をまず製作して、それを素材にして石器（主として打製石器）をつくる場合が多い。